Rafael Nadal has acknowledged the gesture made by opponent Tim Smyczek during the final game of their five-set marathon in the Australian Open second round.

When serving for the match at 6-5 in the fifth set, a spectator shouted out when Nadal was about to serve which resulted in a double fault, but Smyczek, who was two points away from being eliminated, told the umpire to replay the point.

The 28-year-old told reporters: "I want to congratulate Tim because he was a real gentleman for what he did in the last game.

"It was amazing. Not a lot of people would do something like this at 6-5 in the fifth. I think that he played a great match."

Nadal came through the game to win 6-2 3-6 6-7 6-3 7-5 to set up a last-32 tie with Dudi Sela.