There is a case to be made that Brad Gilbert is the busiest man at the US Open, and the former World No. 4 would have it no other way.

From the late hours of Monday evening until the early hours of Tuesday morning, Gilbert sat courtside in Arthur Ashe Stadium to call the fourth-round match between Alexander Zverev and Jannik Sinner for ESPN. He interviewed the winner, Zverev, on court before heading back to his hotel in Queens.

“Last night I got back at let’s say 2:25. And I was up at like, 5:15, probably went to sleep at 3:30. I’ve had probably the least sleep here,” Gilbert told ATPTour.com. “Actually, I was out cold yesterday about 5 p.m. and I got to sleep for about 30 minutes… Then somebody comes, wakes me up, got to go do a hit in the studio. So I get like 30 minutes sometimes during the day.”

Most people on Gilbert’s schedule would be exhausted this deep into the tournament. But the Californian is as fired up as ever.

“I’ve been on every late match. I’m on last tonight again, but it’s okay. There’s nothing better than sitting out there watching something like what happened last night,” Gilbert said. “Actually, I don’t think I’ve ever seen a match like last night. That kind of reminds me of a Rocky Balboa movie.

“I’ve never seen both guys at the same time be dead, out of gas. And then Sinner finally started to look a little better. And then Zverev got one more push. But Zverev looked gone in the fifth, yet he was still serving unbelievably. It was literally a Herculean effort, especially for Sinner, who looked completely out of sorts in the second set.”

Gilbert has been coming to the US Open every year since 1981 and has no plans of breaking that streak any time soon. But this year for the first time the American has combined his commentating with coaching in the same year. Earlier this North American summer Gilbert began working with WTA star Coco Gauff, who on Tuesday advanced to the semi-finals.

“This is the first time I’ve ever done that. So I’ve done all the evening matches,” Gilbert said. “So I’ll be working in the studio doing stuff, then I’ll be working at seven o’clock a little bit, then I get to scout, then I’m courtside for the second match tonight. So they put me to work.”

For the most part, he has not missed any aspect of either role. The only exception has been during qualifying week or missing something on the day of a doubles match. But especially on singles match days, Gilbert has been totally locked in with Gauff.

The former coach of Andre Agassi and Andy Roddick among others, Gilbert is notorious for going on early-morning walks. This US Open has been no exception and after his late night at Flushing Meadows, he walked from 5:15 a.m. until 7:15 a.m. listening to some of his favourite old-school rock music.

“This morning I had a lot of Tom Petty, a little Crowded House, a little Grateful Dead, a little Eagles,” Gilbert said.

How does he stay awake? The 20-time ATP Tour titlist travels with an espresso machine.

“I used to drink a lot more [coffee], especially when I played. Usually I power up with two double espressos in the morning and then usually that’s it,” Gilbert said. “But probably now at like six o’clock or 6:30 before I’ve got to scout the first match and then I’ll be courtside the second one, so I’ll probably have another one at like 6:30, seven o’clock.

“Even when I played in the 80s, I always travelled with my own coffee, like a French press or even at 20 when I went on my first trip to Asia because I wake up early and you might not be able to get coffee. So I always travel with coffee and a way to make it.”

Gauff in a press conference earlier in the tournament revealed Gilbert has given her Jolly Ranchers, which she has not eaten. According to the coach, he used to travel with 500 Jolly Ranchers for a trip. Now ESPN has Jolly Ranchers and an espresso machine on site for him.

“My daughter actually has some healthier ones at home. But when I used to play, let’s say I’d go on an eight or 10-week trip, what happened to Zverev last night used to happen to me,” Gilbert said. “I needed a lot of shoes and you couldn’t get FedEx, you couldn’t get things. So let’s say I’m going on a six or seven-week trip to Asia, I might have to bring 15 pairs of shoes. I’d bring like 500 ranchers for a trip.”

Most importantly, Gilbert loves watching tennis. Even though he is coaching Gauff, he is fully on top of everything going on in the tournament.

“I was thinking we were going to get the Sinner-Alcaraz and I was really looking forward to the rematch of that. But now you’ve got to wonder, a fresh Alcaraz versus 15 rounds for Zverev. Hopefully his team can put him back together. But obviously, advantage Alcaraz at the moment,” Gilbert said. “The crazy one tomorrow [is between Daniil Medvedev and Andrey Rublev]. Rublev’s 0-8 in his career in the [major] quarters and he’s playing one of his best buddies and countrymen.

“Can he get off the schneid? Medvedev, I’ve done like three of his matches here and he’s been fighting himself and everything, fighting his box… but he’s still finding a way. So we’ve got some interesting matchups.”

Gilbert is not sleeping much these days, but as he always says, sleep is overrated.

“There’s nothing I’d rather be doing. I got to play. I got to coach. I got to commentate,” Gilbert said. “I almost feel like I still get to coach even when I wasn’t coaching, when I’m commentating. There’s nothing else I’d rather be doing than doing this run here at the Open.”

Novak Djokovic admitted on Tuesday after advancing to the US Open semi-finals that while he tries to have fun while competing, winning always comes first.

“I’m trying to enjoy the moments on the court, but there is so much stress and pressure going on that it’s hard to have fun, so to say, on the court. It’s really about finding a way to navigate through the match and win a tennis match for me,” Djokovic said. “But off the court, in terms of the actual journey of still being a professional tennis player and going around the world, travelling with my coaching team, we try to keep things light off the court and have fun and enjoy life, because in the end of the day, you have to find that optimal balance.”

The 36-year-old is doing just fine in the winning department. The Serbian is chasing a record-extending 24th major title and by defeating Taylor Fritz in the last eight advanced to a record-breaking 47th Grand Slam semi-final.

“Today it was a great test, to see how it feels being on the court, quarter-finals against a top American. Taylor has been playing some great tennis this tournament, I thought,” Djokovic said. “But I was very determined. I had clarity on what I needed to be doing on the court. Of course, in the heat of a moment, sometimes you want to use that energy to lift yourself up, and sometimes you just want to kind of cocoon yourself and really isolate the noise and focus on breathing and focus on staying present and focussing on the next point.

“So it’s really adapting to whatever circumstances have for you and whatever is required in that moment for you.”

Djokovic explained that sometimes he prefers to “not really pay attention” to what might be happening in the crowd. On other occasions, he likes to feed off fans’ energy.

“I didn’t really want him to win the third set, because then I guess the crowd would really get into it even more and it would become more difficult task for me to handle,” Djokovic said. “It’s normal, it’s logical to expect that most of the crowd would support the home player.”

The three-time US Open champion had not played an American in the quarter-finals of the tournament since he beat Andy Roddick in 2008. He has never faced a home favourite at Flushing Meadows in the semi-finals or later. That will change Friday when he tries to eliminate the winner of Ben Shelton and Frances Tiafoe.

“It’s going to be an American player, for sure. I have to be ready for a great battle,” Djokovic said. “Both of the guys that I’m going to face eventually on Friday, Shelton and Tiafoe, have a lot of charisma. They bring a lot of energy on the court. They are very quick, very powerful.

“Ben Shelton has been serving some bombs this tournament. When his serve is on, he’s a very difficult player to play against, especially because he’s lefty, as well. Then you have Big Foe, who is one of the favourite guys in the locker room, fun to be around, always smiling, always bringing good vibes, and fantastic player.”

Djokovic looks forward to watching the match and preparing to take on the winner.

“I have a couple days off, no match. It actually serves well for my body at this stage of the tournament,” Djokovic said. “I’ll be ready for Friday whoever is across the net.”

Frances Tiafoe was introduced to tennis because his father was the head of maintenance at a tennis facility in College Park, Maryland. Now the American is competing on the biggest stages in the world with countless fans watching him.

That journey is not lost on Tiafoe, who is playing in his second consecutive US Open quarter-final on Tuesday evening against countryman Ben Shelton.

“I fell in love with tennis when I understood the one-on-one competition,” Tiafoe said in a love letter to tennis. “I really enjoy competing one on one, I really enjoy the loss [being] on me, the win’s on me. And I like to feel fully in control and not have to worry about any teammate.”

In the below ATP Uncovered video, Tiafoe explains the ups and downs he has gone through to reach this point in his career, why he enjoys putting a smile on fans’ faces and more.

Which match do you think Tiafoe holds closest to his heart? Watch the video to find out.