John Isner, the reigning Miami Open presented by Itau champion, has made the best Grand Slam run of his career by reaching the Wimbledon semi-finals, where he will face eighth seed Kevin Anderson. And while winning all 95 of his service games has certainly helped at the All England Club, one sweet treat might be the secret to his success, and it’s not an amino acid, a power bar, or anything you might guess.

“I just had a Kit Kat before I came in here. That’s the truth,” Isner told reporters with a smile after his quarter-final victory against Milos Raonic on Wednesday. “I had a little bit of a sugar craving. That’s not a normal occurrence for me. I think after each win throughout these 10 days, I’ve had a Kit Kat. I’m not going to change that now.”

The American hopes that on Friday he’ll be able to continue that streak. And while he has been indulging himself this fortnight, the 33-year-old says he has generally been careful with his diet.

“Especially when I started learning more and more about how important nutrition and diet is, I’ve always eaten very well,” Isner said. “I still eat a lot. I have such a big frame. But for the most part I know what to eat. I don’t eat much pasta. I never eat pizza. I don’t eat much unhealthy stuff. For me, in large part, I’m putting really good fuel in my body.”

The one irony of this story is that Kit Kat’s slogan is, “Have a break, have a Kit Kat’. Isner will be doing his best to ensure that, for the sixth consecutive match this fortnight, there won’t be any breaks – of his serve – against Anderson.

There may not be many people who predicted a Kevin Anderson-John Isner semi-final ahead of this Wimbledon fortnight. But now two of the tallest players in the sport, standing at 6’8” and 6’10”, respectively, have an opportunity to reach arguably the biggest final of their careers at the All England Club.

Perhaps Anderson’s appearance in the semi-final is more surprising, considering the South African was down match point against eight-time champion Roger Federer in the quarter-finals before becoming the fifth player to defeat the Swiss from two sets down. But Isner is not thinking about Federer being out. Instead, he’s focusing on the opponent in front of him.

“Whether it was Kevin or Roger, that didn’t enter my mind at all, which I think is very good,” Isner said. “It’s not like I have a huge opportunity now. Look how well Kevin is playing. It’s going to be extra tough.”

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In fact, both players are in the best form of their lives. Anderson has a chance to reach his second Grand Slam final, and he can break into the Top 5 of the ATP Rankings with a victory against Isner. The American is guaranteed to climb to at least No. 8, which will be a career-best.

And while Isner leads the pair’s FedEx ATP Head2Head series 8-3, they knew one another long before they began playing on the ATP World Tour. The American competed for the University of Georgia, while the South African played at the University of Illinois. Just more than 11 years ago, they battled at the No. 1 singles spot in the NCAA Finals between the two schools, with Isner triumphing in straight sets.

“There could be a little mental aspect in our match,” Isner said. “We’ve been lined up against each other for about 14 years now, because he left Illinois when I left Georgia. We’ve been doing it ever since.

“For me this match-up, and I think for him as well, is especially cool. It’s a very nice spotlight on college tennis, that one of us, no matter what, is going to be playing in the Wimbledon final… I never could have imagined this. I don’t know if you asked him that question [what he would say]. [I would have said] there’s no shot. [I couldn’t] imagine us playing each other in the semi-finals of the most prestigious tennis tournament we have.”

The key will be perhaps how well Anderson, who seeks his 300th tour-level win Friday and has been broken nine times across five matches, holds onto his serve. Isner has not been broken in 95 service games this tournament. So if the American is able to get a beat on his opponent’s serve, that might spell trouble for the 2017 US Open runner-up.

“John I think has got arguably one of the best serves of all-time on the Tour. Especially in the past few months, what’s really impressive is just his first-serve percentage as well, never mind how accurate and big the serve is. But he’s very consistent with the two. Definitely, the first challenge is the serve.”

Isner has landed 75.9 per cent of first serves throughout the fortnight, allowing him to play on his terms from the start of rallies, if the ball comes back at all. Unbelievably, the 33-year-old has hit an ace on 39.7 per cent (161/406) of his first-serve points.

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Anderson knows that Isner, who lifted his maiden ATP World Tour Masters 1000 title at the Miami Open presented by Itau, is high on confidence, allowing him to swing freely at his groundstrokes, especially given his strong serving. So he will be focused on not giving the No. 9 seed any cheap breaks. The American, who is into his first Grand Slam semi-final, has broken serve 15 times in five matches, whereas he arrived on the hallowed grass having broken just 30 times in 25 matches this season.

“In the matches I’ve played him, obviously taking care of your serve is the first priority. It’s a match that’s often won on just a couple points here and there. I feel confident in baseline exchanges I’d say quite a lot [of the time] with John,” said Anderson, who is trying to become the first South African since Brian Norton in 1921 to reach the Wimbledon final. “At the same time, because he’s such a big player, has so much firepower, you just can’t be too patient. You have to still be aggressive, put him on the back foot.”

This year’s New York Open champion uses more topspin from the baseline, allowing him to work points more patiently and play better defensive tennis if need be. This is their first meeting since the 2015 BNP Paribas Open, so it will be interesting to see how they adjust to one another, with both competitors in good form.

“It’s always close, always very close,” said Isner, who can become the 12th American man in the Open Era to make the Wimbledon final.. “When you match up with two big servers, inevitably the matches are going to be close. I’m going to expect a very tough match on Friday. I think he will expect that as well.”

Brad Stine has coached a variety of players throughout his career, from two stints with former World No. 1 Jim Courier to Frenchman Sebastien Grosjean. He had been working with the USTA for three and a half years last December when he got a call that led to him joining Kevin Anderson’s team fresh off the best year of the South African’s career. ATPWorldTour.com sat down with Stine earlier in the season to learn what getting to know the Wimbledon semi-finalist has been like, how he approached their relationship and more.

What made you join Kevin’s team this year? How did that come about?
I wasn’t planning on leaving the USTA, but when the opportunity came up, I really thought it was a great opportunity and obviously Kevin making the final of the US Open last year put him in a pretty elite group and it’s not every day that you get an offer to work with a player who is Top 15 in the world.

I was interested and excited by the opportunity to work with him and he wants to play for another five years or so, and that was important to me. I didn’t want to do it if he’d just be playing for another year or something like that.

What’s been the biggest surprise with Kevin?
I wouldn’t say it’s been surprising, but I would say it’s been enjoyable to be with someone like him. Kevin is probably the most focused, intense professional person I’ve been around since Jim Courier.

What he demands from himself and what he expects from his team when he’s at the office, inside the fences and training is very high.I’ve really enjoyed that, that intensity level and demand. It’s great. It makes me really focused on what’s going on, so to me that’s been the best part of everything.

When guys climb up the ATP Rankings or earn a major milestone in their career, you might not expect them to be looking for a new coach. So how did you approach the situation?
Kevin’s very involved with Jay Bosworth in Delray and they’ve had a long-term relationship around the same length Kevin was with Neville [Godwin], and Jay is still involved, so I’m working closely with Jay. Jay has a very good understanding of Kevin as a person and obviously his game and everything.

But I also wanted to come into the situation with a bit of a fresh eye. I know Neville… I certainly could have reached out to Neville to get some information. But I wanted to come into it a little more fresh and have a little bit more of a beginner’s mindset. I was beginning with Kevin. I wanted to learn and see what was going on. Jay’s made that happen really, really quickly because Jay knows Kevin so well.

Kevin was arguably playing the best tennis of his life toward the end of last summer. So as a coach, how do you approach working with him knowing he’s competing at such a high level right off the bat?
Jay [Bosworth] gave me some good insights as far as some things that they had consistently been looking to improve. Since I’ve been on board there have been a few little technical things and a few little tactical things that we’ve made adjustments in. I’m certainly not going to come on board with Kevin or anyone else in his situation and try and reorganise their game somehow.

Kevin’s obviously been extremely successful and I’ve been lucky enough to work with some top players in the past and recognise that it’s small adjustments that are the difference between winning and losing when you get deeper into tournaments. Kevin’s been lucky enough to pretty consistently get deeper into tournaments.

So when you get deeper into tournaments and you’re playing better and better and stronger and stronger, the margins between winning and losing become really small.So if we could find some small adjustments that help him execute a little bit better in certain situations or create better opportunities for him and be able to stay in points or be able to take advantage of things that he’s created in points, those could be the difference between winning and losing.

Kevin had a tough loss at the Australian Open in your first major together in the first round losing to Kyle Edmund. But then Edmund went on to reach the semi-finals. So how do you deal with a tough match like that so early in a relationship? 
It was obviously disappointing to go to the Australian Open and lose first round. Expectations were pretty high that he could go there and do some damage. The match against Kyle in the first round could have easily been a third-round match or a fourth-round match. And it was a great match regardless of where it happened in the draw. It was disappointing to lose, Kevin was up a break early in the fifth set, it felt like he had a good opportunity.

We had been to two events prior to that and had been on the court for a week of training in Melbourne and a week or so in Delray prior to that so we hadn’t been together for long. I felt like we really clicked quickly. We get along well. The level of communication has been very good between Kevin and I and between Jay, myself and Kevin. We have an open chat between the three of us all the time with the phone. But I was really impressed both in Pune when he lost to Simon in the final and then again when he lost to Kyle in Australia with his level of maturity.

Of course, Kevin is a more mature guy for the Tour, but his level of maturity with how he dealt with those losses and kind of sitting down and analysing the situation [was impressive]. What were the positives? What were the negatives? What were the things we need to take from those things to improve on? We talked about those things and we’ve tried to address some of the things that I saw when he played Kyle in Australia as things that may have presented themselves against that particular opponent as things that I think he can apply in matches day in and day out so it’s an educational process.

Kevin’s got a very good outlook. I’d say he’s very good with his growth mindset of getting better and I have found him to be very open about discussions in relationship to making the adjustments that we’re talking about and applying different things and the willingness to do that and that’s made it really enjoyable so far from where I’m at.

You have a lot of experience with a variety of players, so how do you go into a coaching relationship? How do you balance adapting to the player versus bringing your own ideas to the table?
I think it’s a combination of both. I think at this point in my career, coaching wise, there are certain things and philosophies I’m set with. But I think part of being a good coach is actually being able to look at the strength and weaknesses of each individual player you’re working with and being able to get the most out of them. Working with Kevin is going to be different than working with Sebastien Grosjean or with Jim [Courier]. It’s what Kevin brings to the table and then what I can bring to try to improve where he’s at because that’s the goal.

And again, that’s been one of the refreshing things with Kevin, who at 31 years of age and being ranked where he’s ranked, he still feels that he has definite room to improve and get better and that’s what he’s looking for. He wants to improve. He wants to be ranked higher than where he’s at. He wants to continue to be going deep in big tournaments and giving all kinds of trouble to the guys who are in front of him as well as the guys who are behind him. So it’s been really refreshing from that standpoint. I think what I have to do is make sure that I’m getting my message across with the things that I see and the things that I recognise that are things that I’ve learned over the years from all the guys that I’ve coached and then apply to him, but within the context of what he does also. I think that’s important.

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