Nadal lost the first set 7-5 and during the changeover between sets, the tournament trainer put strapping around his right knee.
And before the start of the third set, Nadal received additional strapping to his knee.
Nevertheless, Nadal was able to come through and win in four sets 5-7 7-5 7-6 7-6.
Speaking in his press conference, Nadal calmed fears of a serious issue.
Nadal said: “Just something that I felt, but I try always during the tournaments don’t speak much about these kind of things.
“When the tournament is over is better and easier to talk.
“But my personal feeling is I going to be at my 100% for the next one.”
But Nadal did admit the match was physically and mentally draining for him.
He said: “I went through some very difficult situations.
“It was a physical, demanding match. It was a mentally demanding match.
“That’s why we practice every day, to play these kind of matches in a great atmosphere in front of an amazing crowd.
“Yeah, very happy to be through. Very happy to have the chance to play again.”