There are signs that Denis Kudla is getting back to his best.

After reaching a career-high No. 53 in the ATP Rankings on 23 May 2016, Kudla saw his ranking slowly drop until falling outside of the Top 200 towards the end of 2017. But, after a strong final run in Knoxville (l. Peliwo) on the ATP Challenger Tour, Kudla ended his season with great cause for optimism.

In 2018, Kudla has already built on that strong showing in Tennessee, qualifying for his first Grand Slam main draw since the 2016 US Open, winning four matches and forcing No. 5 seed Dominic Thiem to five-sets in a second-round loss at the Australian Open. This week, he is into the quarter-finals at the RBC Tennis Championships of Dallas, a $125,000 Challenger. The American has not dropped a set thus far.

After working with Dustin Taylor in the off-season and spending his time between the Harry Hopman Tennis Academy in Tampa and the USTA National Campus in Orlando, Kudla is confident about the state of his game moving forward in 2018.

“I worked a lot in the off-season,” said Kudla. “I worked really hard to find a little bit more consistency, work on my serve and bring back high energy tennis which I ran away from a little bit.

“I am a guy that brings a lot of energy and wins with fitness and tangibles, so right now… I feel fit and the game is where it needs to be.”

The 25-year-old, who turned professional back in 2010, has plenty of ideas on how he can improve his game and get back into the Top 100 this year with one key factor as the main focus.

“Finding more balance,” said Kudla. “I did a lot more cardio… so I could sustain a higher level of tennis for a longer period of time. That was a big thing. I knew the game was there but I kept dying at a certain point and I realised I just wasn’t in good enough shape. I thought I was but I wasn’t. So that was the biggest thing, when I know I’m in shape, the game is there. It has always been there.”

That extra work in the gym was certainly evident in his five-match run in Melbourne and he was back at work at Challenger level in Newport Beach last week where, despite losing to Reilly Opelka in first-round singles action, he made the doubles final with partner Treat Huey (l. Cerretani/Paes) .

Playing his opening match in Newport Beach just five days after his last match in Melbourne is no easy matter, but for Kudla, with determination to climb the ATP Rankings in 2018, the motivation to succeed is stronger than ever.

“I am incredibly motivated,” said Kudla. “I do believe I am going to have a good year this year as long as I continue to do the right things, but I have a great team around me, playing well. As long as I don’t lose focus and get satisfied, I think I’m going in the right direction.”

Kudla managed to win four matches in Melbourne from first round qualifying, with three of his wins coming against higher ranked opposition, before falling to Dominic Thiem in a bruising five-set encounter. Reflecting on his great efforts at the first Grand Slam of 2018, Kudla expressed his delight at the start he has made to the new season.

“It was a great week for me to qualify and win a round, especially against Steve Johnson who is a good friend of mine and had my number, so it was nice to get that. Then to push (Dominic) Thiem to five sets, I put myself in a good position to win. I was just happy that I was able to bring my game around for five consecutive matches; I haven’t been able to do that for a long time,” admitted Kudla.

“I was up two-sets-to-love against a Top 5 player in the world… I can play right now, with top guys. I need to transfer that into the next couple of tournaments and start this year on a high note… and carry it over for as long as I can and hopefully get back in the Top 100,” said Kudla.

That confidence will surely help Kudla this week as he competes in Dallas on the Challenger circuit once more. The American also emphasised his desire in 2018 to focus on the process, rather than setting a specific numerical goal in the ATP Rankings.

“I tried not to set a ranking goal this year,” said Kudla. “Obviously in the back of my mind I want to be Top 100 and back in the Grand Slams but [my goal] is to be consistent, learn from my mistakes and stay fit, not losing my shape throughout the year. If I can do that, I can play at a high level and I’ll get the match wins that I need.”

Former World No. 4 Kei Nishikori continues his comeback on Wednesday evening at the RBC Tennis Championships, an ATP Challenger Tour event, in Dallas. The top seed faces German Matthias Bachinger in the second round. The match will begin at 8 p.m. ET, and you can watch it live below. Nishikori missed the final four months of the 2017 season after having surgery on his right wrist.

Spain’s Guillermo Olaso thought it was never going to end.

Olaso and Russian Evgeny Karlovskiy played a 42-point tie-break during the opening set of their qualifying match on Monday at the RBC Tennis Championships of Dallas, an ATP Challenger Tour event.

Both players had a number of set points; Olaso saved 10 and clinched the set on his seventh. The tie-break is the longest for an ATP Challenger Tour qualifying match.

“Normally a tie-break never lasts that long,” Olaso said. “It feels like we played another set almost, because it took so long and it took a lot of energy out of both of us.”

Perhaps the tie-break took too much out of him. He eventually lost 6-7(20), 6-1, 7-6(5).