Stefanos Tsitsipas may have attracted a legion of new followers for his on-court performances at the 2019 Australian Open, but the Greek star has also proven to be a favourite on social media.

Since beating Roger Federer in the fourth round on Sunday, Tsitsipas’ subscriber count on his YouTube channel has soared to beyond 100,000. Read More

And his channel has attracted the attention of American YouTube personality Casey Neistat, who has more than 10 million followers. Neistat has now called on the 20-year-old #NextGenATP player to collaborate with him, and Peter McKinnon, another popular YouTuber, after Tsitsipas leaves Australia.

Tsitsipas lost to 2009 champion Rafael Nadal on Thursday night in the Australian Open semi-finals.

On Monday night, after his taxing fourth-round contest with Daniil Medvedev, Novak Djokovic was exhausted. He put on a front in his on-court interview with Jim Courier, puffing out his chest and flexing his arms, as if to say, “Nothing to see here!”

But later, he shared just how the three-hour and 15-minute grind had affected him.

Game face #AusOpen pic.twitter.com/eiI79Utjm6

— Novak Djokovic (@DjokerNole) January 22, 2019

“I didn’t feel so great in the last 20 minutes of the match or so… It was just a little bit of fatigue… Nothing major. But there are a couple of things that have surfaced, so to say, after a match like this,” Djokovic said.

He didn’t doubt, however, that he’d be ready for his quarter-final against Kei Nishikori. But Djokovic also didn’t mind his quick night at the office on Wednesday evening, when Nishikori retired down 1-6, 1-4 and after only 52 minutes.

“As they say, this is exactly what doctor ordered,” Djokovic told Courier after making his 34^th Grand Slam semi-final. “After a match two nights ago, not to spend too much time on the court, and I’ve had plenty of matches so far this year. I’m in another semi-finals, and I’ll do everything to get ready for that one.”

His seventh Melbourne semi-final, despite Djokovic’s surplus of final-four matchups, will be a new experience: The Serbian will meet Lucas Pouille for the first time. The Frenchman ended Milos Raonic’s bid for a fourth Grand Slam semi-final, and has been playing the tennis of his life, the type of tennis fans and pundits thought they’d see from Pouille at every tournament since he won his first ATP Tour title in February 2016 at the Moselle Open.

But last year, after debuting inside the Top 10 in March, he lost his way. Pouille wrestled with self-belief and questioned his desire.

“It came really fast when I did a quarter-final in [2016] Wimbledon, US Open, then the year after I didn’t win a lot of matches, but I still finished 17 in the world. Last year I lost a bit of joy to be on the court, didn’t want to live in the tournaments,” Pouille said.

Watch: Pouille’s Journey To Professional Tennis

“I took some time to think about myself, about my career, about what I wanted to do. I said, ‘Okay, you have maybe 10 more years on Tour. Do you want to spend them like this or do you want to enjoy it, to enjoy playing on the biggest courts of the world in front of some unbelievable crowds, achieve some great goals, great titles?’

“I said, ‘Okay, now you have to move your ass a little bit and go back to it. Even if you don’t want to practise one day, don’t do it. Just do it when you want. That’s how it came back.’”

Pouille split with Emmanuel Planque in November, and in December started working with former WTA No. 1 Amelie Mauresmo, a two-time Grand Slam champion, including the 2006 Australian Open.

The dream goes on!!!! #SemiFinals #LockedIn ?? again for your support, it means a lot to me!! ? ? ??????? @AustralianOpen (? @antoinecouvercelle ) pic.twitter.com/OicsrfboN9

— Lucas Pouille (@la_pouille) January 23, 2019

“Started a new adventure with my team, with Amelie, with Loïc [Courteau of the French Tennis Federation]. I think that was the great thing for me. I want to practise. I enjoy being on the court again. That’s the most important,” Pouille said.

In a way, his status towards the end of last year wasn’t all that different from Djokovic’s in January 2018. The Serbian never questioned his desire to play and the satisfaction he derived from sport, but he has admitted to feeling lost on court during the early stages of his comeback from a right elbow injury.

Watch: Behind The Scenes of the ATP Photoshoot with Djokovic

You wouldn’t know that Djokovic has struggled in the beginnings of seasons, however, by looking at his Australian Open ledger. The 31-year-old is chasing a record seventh title and has dropped only eight matches from 74 contests at Melbourne Park.

“Being one of the four biggest events in our sport, a Grand Slam, just extracts a lot of motivation and inspiration to play your best always, to get ready, to start the season in the best possible fashion,” Djokovic said. “I have the greatest memories from this court and from fans that have been supporting me over the years.”

He’s back in top form, and Pouille has never played better. “A battle” is what Djokovic is expecting from the Frenchman who upset Rafael Nadal to make the 2016 US Open quarter-finals.

“He’s not afraid to play his best at the biggest stage in sports. So I expect him to come out, be very confident about himself as he always is,” Djokovic said.

“What he has done this tournament is fantastic… With the quality of the tennis that he possesses, he deserves to be definitely at the Top 15, maybe Top 10 of the world. He’s got that quality and potential, no question about it.

“It’s funny that we’re going to play first time against each other. We’ve practised many times. We’ve known each other obviously for a long time… Hopefully we can both be fresh and fit and put on the great show.”