Four weeks ago, he needed a wheelchair to get off the courts at the French Open.
Three weeks ago, he underwent surgery to repair damage to his right knee.
But on Thursday, 23-year-old Taylor Fritz of the United States confounded all medical logic by reaching the third round at Wimbledon.
"I'm positive this is the quickest anyone has ever returned to actual professional competition from this surgery," said Fritz after seeing off compatriot Steve Johnson 6-4, 7-6 (7/4), 4-6, 6-7 (4/7), 6-4.
Fritz, the world number 40, suffered the injury in a second round defeat at Roland Garros.
"I tried to stand up. I couldn't stand. I looked at my team, and I said, guys, I could be done for a long time. I heard it pop."
He was told that he was looking at a four to six week recovery but his surgeon in California had relatively good news.
There was no serious damage to the meniscus in the right knee.
"He told me before we went in that he just has to snip the part that I tore off, just snip it out, and then we're good, because the rest of the meniscus looks intact," explained Fritz who still requires a surgical support on the knee when he plays.
Coloured black, it's the only non-white clothing item on the courts at the famously strict All England Club.
"But he still warned me that if it's a little bit damaged, then I'm going to have to do a repair.
"First thing when I woke up, I was loopy from the anesthesia, and the first thing I said was, Did he repair it or did he snip it? They said, He snipped it.
"Immediately from then on I was just thinking, like, Wimbledon, everything I can possibly do to be here."
Fritz has certainly given the knee a decent road test.
He has played nine sets of tennis in 26 hours to get to the last 32 where he will face German world number six Alexander Zverev.
"I have already done more than I think myself or anyone else expected," said Fritz.
"Nine sets in the last 26 hours, three weeks out of a knee surgery. It's all positives, no matter what happens.
"I'm just going to go out there and go for it. Maybe this crazy run can continue."
Third round opponent Zverev, a rival of Fritz since their junior days, is astonished by the American's recovery.
"I'm very surprised that he's actually playing here and I'm very surprised how well he's playing," said Zverev.
"I have to give credit to him for coming back this quickly."
Fritz won his only career title on grass in Eastbourne in 2019.
Zverev defeated him in five sets at Wimbledon in 2018.
"I think on a grass court he's extremely dangerous. He has a very fast serve, has big weapons," said 24-year-old Zverev.