MELBOURNE, Australia (AP) -- Novak Djokovic got a huge scare from 15th-seeded Stanislas Wawrinka before hanging on to win in the 22nd game of the fifth set to advance to the quarterfinals of the Australian Open.
The top-seeded Djokovic needed 5 hours, 2 minutes for a 1-6, 7-5, 6-4, 6-7 (5), 12-10 victory that ended early Monday morning.
Djokovic broke Wawrinka's serve in the final game to clinch the win on his third match point with a cross-court backhand.
Djokovic is the two-time defending champion and has an 18-match winning streak at Melbourne Park. He is trying to become the first man in the Open era to win the tournament three times in a row.
Meanwhile, Maria Sharapova has lost only five games in four matches on the way to the quarterfinals, a record that seems to be immaterial to the 25-year-old Russian.
The No. 2-ranked Sharapova beat Kirsten Flipkens of Belgium 6-1, 6-0 on Sunday to continue a dominant and unparalleled run.
"Well I'm certainly happy to be playing this well but ... it only gets tougher from here,'' said Sharapova, who is playing her first tournament of 2013 after withdrawing from an exhibition match in South Korea and a warmup event at Brisbane because of an injured right collarbone.
Steffi Graf conceded only eight games in her opening four matches here in 1989, when she won the second of her three straight Australian Open titles. Monica Seles matched that mark.
Sharapova has been even more dominant. She started with a pair of 6-0, 6-0 wins -- the first time that has happened at a major since 1985 -- and then beat seven-time Grand Slam winner Venus Williams 6-1, 6-3 in the third round.
The reigning French Open champion is showing no signs of trouble with the collarbone in Melbourne, where she last won the title in 2008.
"The year that I won here I don't think there were many games that I lost, but I don't think it was five or six,'' she said, reflecting on a run to the title where she beat three players who'd been ranked No. 1. "Toughest draw in my career.''
It hasn't been as tough this year, but she next plays fellow Russian Ekaterina Makarova, who ousted fifth-seeded Angelique Kerber 7-5, 6-4. Sharapova beat Makarova in the quarterfinals here last year on her way to the final.
She did struggle at times against Flipkens, needing more than 11 minutes to hold serve in the fourth game, when she served three double-faults and had to fend off three break points.
"No matter what the score is, no matter if you're up. You know, I didn't start the match really great,'' she said. "I was facing a different type of opponent today and I was making a few more mistakes than I would have liked in the beginning.
"But after I held at 2-1, I really started making her play a little bit ... and I carried that throughout the match.''
Sharapova had to beat former No. 1 Justine Henin in the quarterfinals when she won here in 2008. Last year, she beat Makarova at the same stage en route to the final. Makarova, ranked 19th, is better prepared this time.
"I really want to play against Maria,'' Makarova said. "Now I'm pretty confident and I like my game.
"Last year I was so surprised ... and I had so many thoughts in my mind. This year I'm a little bit used to it, so I think I'll be ready to play a good game.''
Makarova took out the highest seed to tumble so far at the season's first major, causing another fourth-round surprise like she did here last year with an upset win over Serena Williams.
Kerber and Makarova were two of only four women in 2012 to beat Williams, who lost only one match in the second half of last season as she collected titles at Wimbledon, the London Olympics, the U.S. Open and the WTA Championships.
"Seems like it was the same this year and last year. Unbelievable feeling,'' Makarova said. "I really like to play here. The crowd is so perfect.''
In a later fourth-round match, 2011 finalist Li Na saved a set point in the tiebreaker before beating Julia Goerges 7-6 (6), 6-1. She'll next play the winner of Sunday's later match between No. 4 Agnieszka Radwanska and No. 13 Ana Ivanovic in the quarterfinals.
In men's matches, fourth-seeded David Ferrer had a 6-2, 6-1, 6-4 win over No. 16 Kei Nishikori of Japan to reach the quarterfinals, where he will meet Spaniard Nicolas Almagro.
Nishikori had won two of his previous three matches with Ferrer and was a quarterfinalist in Australia last year, but struggled with 65 unforced errors in the 2-hour, 10-minute match.
Almagro advanced later Sunday, leading 6-2, 5-1 when No. 8 Janko Tipsaveric retired from their fourth-round match.
It will be the first all-Spanish quarterfinal at the Australian Open since 2011, when Ferrer ended Rafael Nadal's bid for a sequence of four consecutive major titles.