Spaniard Rafa Nadal admits he had doubts "every single day" about whether he would ever return after missing the second half of 2021 because of a foot injury.
The 35-year-old looked in prime form as he beat Karen Khachanov on Friday to reach the Australian Open fourth round, just weeks after a resuming competitive action.
It kept him on course for a men's record 21st Grand Slam singles title, but Nadal says he is just happy to be back competing after the dark days of last year.
"I mean, everybody around me, me included, had a lot of doubts. Not about the Australian Open, no, but about coming back on the Tour because the foot was bothering a lot of days," Nadal, who missed last year's Wimbledon, the Tokyo Olympics and the US Open, told reporters.
"Of course, I still today have doubts because the foot, as I said the other day, is an injury we cannot fix. So we need to find a way that the pain is under control to keep playing.
"The movements, all this stuff, you need to recover day by day. There is no way to recover that without competing."
With three supremely confident wins in Melbourne, following his title at an ATP warm-up event in the city, 2009 champion Nadal appears to be playing freely and has come a long way since even getting through a practise session was an achievement.
"For a lot of months sometimes I went on court and was not able to practise more than 20 minutes, on other days for 45. And then sometimes I was able to practise for two hours," Nadal told Eurosport after his win.
"It's been very difficult to predict every single day and I was working with a doctor to try and find a solution. I tried different things but it's tough."