The Austrian’s stunning win against Novak Djokovic on hardcourt this week was proof Thiem has made the leap from claycourt specialist to all-round superstar.
He attacked when under pressure and out-gunned the impenetrable Djokovic in hitting duels.
Thiem said it was a career-best performance, as did his ATP Cup captain Thomas Muster.
In his eyes, Thiem is now a legitimate grand slam contender who can threaten the big three on all surfaces bar grass.
“It’s always great to say you have played your best match ever but I think he has stepped up, there’s no question,” Muster said.
“You take grass away but on any other surface – indoors, outdoors, he’s improved a lot in the last few months.
“He has tried different things to make that better and it is coming out. It’s showing already.”
Thiem will launch his assault on the 2020 season in Sydney at the ATP Cup, where Muster believes he can start to position himself as the next man to claim the world No.1 ranking.
“We still have a long way to go before he steps up to the level where he is on clay. That’s great, in his position, to be able to say that. Because he has quite a few years ahead of him. If he had nothing to improve, that would be terrible,” he said.
“The potential is there and looking at it from his point of view, if you’re No.4 or 5 in the world, the next goal has to be No.1 in the world.
“To have the ATP Cup at the beginning of the year, you get to see what all the practice sessions over the winter have done.
“You get the opportunity to make the next step forward and it will be great to work with him before the ATP Cup and during the Cup, just before the Australian Open.”
Thiem aside, the ATP Cup will provide a launch-pad for the other rising stars ready to challenge the big three.
Rising Russian Medvedev is the other obvious threat to Federer, Nadal and Djokovic.
The US Open finalist will kick off his season in Perth but Brisbane will host Greek 21-year-old Stefanos Tsitsipas, German 22-year-old Alexander Zverev and Australians Nick Kyrgios and Alex de Minaur.
Zverev’s ATP Cup captain, six-time grand slam winner Boris Becker, takes little confidence from his country’s 2018 Davis Cup tie win over Australia at Pat Rafter Arena.
The reason for his pessimism? The rapid improvement of de Minaur.
“De Minaur was in his very first Davis Cup tie (when Germany last faced Australia). He’s a lot better now,” Becker said.
“A lot better. What he’s missing, I think, at times, is experience. But he’s on a real journey right now and he’s not far off. He will get there.”
Then there’s Kyrgios. He may not have a spot in the world top 10 like many of the other rising stars but his potential is arguably greater than all bar Thiem.
“Nick (Kyrgios) has a point to prove. He likes Brisbane, he likes Pat Rafter Arena. He’s won the tournament there before,” Becker said.
“It will be difficult for Germany but we like the challenge.”
Kyrgios won’t be the only player with a point to prove at the ATP Cup.
Thiem, Medvedev, Tsitsipas, Zverev, Italian Matteo Berrettini, Canadian Denis Shapovalov and de Minaur are in a seven-way race to take the mantle from the big three as the next superstars of world tennis.
Federer, at 38, didn’t look a day over 30 as he wiped the court with Djokovic in London on Friday.
But Becker believes the passing of the torch has finally arrived.
“We’ve been wondering about the top three and when the time will actually arrive,” he said.
“They are three legends of the game and they keep improving. That makes it a challenge for the younger generation but ultimately, time waits for no man.
“Sooner or later – and it might be next year – the passing of the torch will happen.”
Sam is a sports reporter for The Sydney Morning Herald.