Novak Djokovic was "playing for history" and suffered from nerves in his US Open final defeat to Daniil Medvedev, according to previous champion Dominic Thiem, who backed the 34-year-old to return "stronger than ever" in 2022.
Medvedev prevented Djokovic from becoming the first man since Rod Laver in 1969 to win all four grand slams in a single year, beating him 6-4 6-4 6-4 in Sunday's thrilling showpiece.
Djokovic was seen in tears during the third set as his hopes of adding the US Open to his run of wins at the Australian Open, French Open and Wimbledon this year slipped away.
But Thiem tipped Djokovic to bounce back from the disappointment of defeat and return in 2022 even stronger.
"One unbelievable goal slipped out of his hands yesterday," Thiem told Stats Perform.
"I expect him to be as strong as ever in 2022. I think after he won in Roland Garros, everybody was only talking about the calendar slam – first about the golden slam, and then about the calendar slam.
"He [Djokovic] was under pressure. Nobody can feel that or anything like that because of it being the calendar slam.
"I can feel it in a smaller way, probably from last year's final and from some other matches. And at some points it's just getting to you. And so, I really felt for him as well towards the end of the match.
"So, it can happen that it also makes him even stronger next year when all these talks and all this pressure is not that big anymore."
Thiem, who missed the tournament with a wrist injury that will rule him out until 2022, believes nerves were a factor in Djokovic's defeat but agreed with Medvedev's assessment of the Serbian as the greatest of all time – though he could not set him apart from Roger Federer and Rafael Nadal.
"For me, there are three GOATs in the game, and each of them has achieved something very unique," Thiem said of the trio locked on 20 major titles each.
"So it's still the same for me as it was before. The three of them are the best in the history to me.
"And I'm only super happy to be in the same era with them and to be able to compete with them. Hopefully many more times next year again."