MELBOURNE, Australia (AP) -- Tennis fans learned two things about Rafael Nadal. He doesn't like sleep or math.
The 14-time Grand Slam winner advanced Friday to the fourth round of the Australian Open, beating Dudi Sela in straight sets. He expended much less time and energy than he had in his 5-set, third-round match that lasted over four hours.
On-court interviewer Jim Courier asked Nadal if he had done anything special to recover between the two rounds.
''Sleep?'' Nadal replied, prompting Courier to ask if he normally doesn't sleep between matches.
''Seriously, I don't like to sleep a lot. I feel that when I am sleeping that I am losing time,'' Nadal said.
Ahead of the tournament, the 28-year-old Spaniard insisted he was not match fit in the wake of a right wrist injury and appendix surgery that sidelined him for much of the last half of 2014.
Courier tried to get Nadal to quantify how he feels, asking him on a scale of 0 to 100 percent how does he feel physically? Courier, who won four Grand Slams before retiring, waited as Nadal gave a long response that didn't answer the questions. He pressed him again.
''I want a number,'' Courier said.
The crowd laughed, and Nadal did, too.
''I was never very good at mathematics,'' Nadal said.
LAUGH IT OFF: When you're getting trounced by Rafael Nadal and you can't even get a call to go your way, sometimes you just need to laugh at the situation.
Dudi Sela was trailing 6-1, 4-0 in his third-round match against Nadal at Rod Laver Arena when he hit a beautiful running forehand passing shot that appeared to clip the line. Nadal challenged the call, however, and the video review showed it was out.
Stunned, Sela smiled and held up his arms in disbelief. He then appealed to Nadal's generosity and held up a finger as if to say, ''C'mon just give me one?''
Nadal smiled and the crowd began to laugh. The point, however, went to the Spaniard.
''For the crowd, they paid money and I don't want them to go after 45 minutes, so I tried to do something,'' Sela said. ''Tried a little bit to entertain.''
POKER FACE: Some players cheer themselves on after great shots or vent frustration at the bad ones. Not Maria Sharapova.
The No. 2-ranked Sharapova keeps a poker face, which was on display Friday as she cruised to a 6-1, 6-1 win over Zarina Diyas in the third round. The match lasted a mere 61 minutes.
Afterwards, on-court interviewer Rennae Stubbs, a retired Australian player, joked that she wanted Sharapova on her poker team.
''That would be a terrible decision, Rennae, because I'm terrible at poker,'' Sharapova laughed.
''The only thing I've ever played was blackjack. And I'm terrible at that, too,'' she added.
The five-time Grand Slam winner faces China's Peng Shuai on Sunday in the fourth round. The No. 21-ranked player from China plays with two hands on both forehand and backhand, yielding flat, deep shots.
''She's a bit of an untraditional player with two hands on both sides. That's a little tricky,'' Sharapova said. ''Yeah, I look forward to a good match-up.''
BATTLING THE GREEKS: Was it a third-round men's singles match at the Australian Open or a football match between Greece and Bulgaria?
With the amount of noise coming from Court 3, where Bulgarian Grigor Dimitrov played Greek-Cypriot Marcos Baghdatis, it was hard to tell.
Baghdatis, the 2006 Australian Open finalist, has long drawn vocal support from Melbourne's large Greek community over the years, and his fans were out in force Friday, chanting, serenading and clapping vigorously for him.
Dimitrov's fans, clad in the green, white and red colors of Bulgaria's flag, were drowned out at times, but their man didn't need as much help. No. 10-seeded Dimitrov rallied from a set down to beat an inspired Baghdatis 4-6, 6-3, 3-6, 6-3, 6-3.
''Marcos has always been a favorite guy out here,'' Dimitrov said. ''I like it when the atmosphere is like that. Actually fills me up with positive thoughts. At the same time, it's nice to prove (the crowd) wrong.''