Rafael Nadal survived an epic five-set encounter with American Tim Smyczek on Day 3 in Melbourne, but instead of feeling overjoyed, the experience left the 14-time Grand Slam champion a little puzzled about his health.

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“I was suffering a lot,” said Nadal. “Too much. You know, was not funny today the way that the match was. Obviously is a very positive thing that finally have the chance to win, but, yeah, I hope to recover myself.”

Nadal was clearly not himself for most of the night. At times he was seen doubled over after points, and he had the trainers visit him and give him pills during the match.

Nadal says that he was close to throwing in the towel, but that he found a way to conserve energy in the latter stages of the match and he eventually felt somewhat better.

“I was close to not continue because I felt that I was very dizzy,” he said. “I felt that I can lose little bit the - I don't know how to say - can fall down. So is true that after the third, fourth, and fifth, I tried to play much more aggressive, without running, no running anymore, and try to go for the winners and play little bit better, play little bit more relax. In terms of physically, at the end of the match I started to felt little bit better.”

His opponent noticed Nadal’s form, and for a moment during the fourth set, he felt he was headed for the biggest win of his career.

“Yeah, I thought I had him for a minute,” said Smyczek. “When he was kind of doubled over I could see he was really hurting. I started to believe that I really, you know, had a chance and could get it done. But he turned it up to another gear. That's why he's been one of the best for years and years.”

Nadal was relieved to get the victory, but he still isn’t sure why he had no energy during the match, or what he can do to improve. For now, he just plans to rest and hope that he feels better in his next match.

“I don't know,” he told reporters about the nature of his illness. “I don't know yet. I just go out. But is true that the weather was different today than the last couple of weeks. Very humid. I am sweating a lot always when it's humid. “But, I don't know, long time without competition, with tough conditions, but at the end happened something more. Is obvious, no? I practiced a lot. Should not be that tired after 40 minutes. That's obvious, no? Something happened, and I feel lucky to have the chance to finish the match, and then to find a way to win. So very positive for me. As I say the other day, all the moments I spend on court are important. Is not positive be like this, but in general you know important to win these kind of matches. That's give me the possibility to play again, and I going to try to make better the next day.”

Nadal will face Israel’s Dudi Seli in the third round.