MELBOURNE, Australia — Serena Williams' 17-match winning streak at the Australian Open ended Monday in a stunning 6-2, 6-3 loss to Ekaterina Makarova, the lowest-ranked woman in the fourth round.
The dominant force at Melbourne Park this century, Williams had lost only two matches at Melbourne Park since winning the first of her five Australian Open titles in 2003. After losing in the 2008 quarterfinals, she won titles in 2009 and 2010 before sitting out last year because of injury.
But she had seven double faults — four in the fifth game of the second set — and 37 unforced errors to give the 56th-ranked Makarova a spot in the quarterfinals at a major for the first time.
"Uhm, I think she played really well. She went for broke on a lot of her shots," Williams said. "I made 37 errors. That kind of tells the story of the match."
Makarova, who surprised Williams with the power of her ground strokes, will play either 2008 champion Maria Sharapova or Sabine Lisicki.
"I don't know what to say. Amazing feeling and first time in quarterfinals," the 23-year-old Russian left-hander said. "(Williams is) an unbelievable player. It's really tough to play against her so I'm really happy I finished it in my way."
Williams sprained her left ankle in a warmup tournament at Brisbane two weeks ago, but didn't show signs of being seriously restricted Monday.
She was bothered by a bug that landed on her left shoulder when she dropped serve for the first time in the match, and became increasingly exasperated as her misses piled up — including one overhead that she sent way too long and another that she hit meekly back for Makarova to pass her.
Williams won the first two games in the second set but then Makarova went on a roll, winning the next four — including the double-fault strewn game at 2-2 when Williams screamed after one and asked herself out loud after another: "How many double-faults do you want to make?"
Williams didn't blame her ankle injury or the heat, which increased to 93 during the day, but couldn't even describe how bad her serve was.
"Yeah, I served like a ... I guess that's not appropriate. I served, I don't know," she said, struggling for an explanation. "It was disastrous really. My lefty serve is actually better than that. Maybe I should have started serving lefty."
The 13-time Grand Slam winner had only played two competitive matches since losing the U.S. Open final to Sam Stosur last September, and her light preparation was curtailed further when she badly twisted her ankle as she won her second-round match at Brisbane earlier this month.
"I'm feeling fine. Obviously I'm not 100 percent, and I haven't been," she said. "But it's no excuse or anything.
"Usually I play myself into the tournament, but I don't have a huge problem with an injury — so this is a completely different situation. Usually it's easier for me to play myself in because I'm usually physically OK."
Makarova got tighter toward the end but kept her nerve to hold in a key game. Then, with Williams serving to stay in the match, she needed four match points before Williams sent a backhand wide.
The absence of Williams opens up the women's draw, with Sharapova, defending champion Kim Clijsters and Wimbledon winner Petra Kvitova the only major winners still in contention. Clijsters advanced to the quarterfinals with a comeback win over Li Na on Sunday in a rematch of the 2011 decider, while Kvitova had some trouble late before beating former top-ranked Ana Ivanovic 6-2, 7-6 (2) in the opening match Monday.
The 21-year-old Kvitova was seemingly fast-tracking her progress to the last eight until her game momentarily came undone near the end of the second set after she completely missed a routine overhead at the net to allow the former French Open champion to pull to 4-5.
She lost the next eight points to fall behind 6-5 — badly missing on a couple of wild groundstrokes — and only managed to force a tiebreaker with two big serves out wide in the 12th game.
Ivanovic's two double-faults early in the tiebreaker gave Kvitova some easy points and took the pressure off.
The match seemed close to ending much earlier when Kvitova got into perfect position to put away an innocuous lob from Ivanovic, but played through the shot too quickly and was hit instead on the body.
"It was a very tough match at the end. I mean it was a really easy point then I thought I got it and I lost eight points in a row," she said. "I'm very happy I played very well in the tiebreak."
She'll face Sara Errani of Italy, who beat 2008 semifinalist Zheng Jie 6-2, 6-1.
On the men's side, two-time Australian Open runner-up Andy Murray only spent 49 minutes on court and was leading 6-1, 6-1, 1-0 when Mikhail Kukushkin retired from their fourth-round match with a left hip injury, giving him an easy path into the quarterfinals.
"It's obviously good for me, I get to conserve some energy," Murray said. "Tough for him, first time in the fourth-round of a Slam."
He'll play Kei Nishikori, who had a stunning 2-6, 6-2, 6-1, 3-6, 6-3 win over sixth-seeded Jo-Wilfried Tsonga, the 2008 finalist.
The 22-year-old Nishikori became the first Japanese man to advance to the Australian Open quarterfinals in 80 years, and the only the second man from his country to reach a Grand Slam quarterfinal in the Open Era started in 1968. Shuzo Matsuoka reached the 1995 Wimbledon quarterfinals.
Defending champion Novak Djokovic was playing Lleyton Hewitt on Monday night.
On Sunday, Clijsters set up a quarterfinal against top-ranked Caroline Wozniacki, who had a 6-0, 7-5 win over former No. 1 Jelena Jankovic. Wozniacki is yet to win a major, but her confidence is high.
"If I play like I did today, Kim will have to really play well to beat me," she said.
Clijsters needed pain killers to get through the 2-hour, 23-minute win over Li and she's hoping ice treatment will help her recover in time for the quarterfinals.
Third-seeded Victoria Azarenka advanced with a 6-2, 6-2 win over Iveta Benesova. She next plays eighth-seeded Agnieszka Radwanska.
Roger Federer more or less held a clinic at Rod Laver Arena, where he has won four of his 16 Grand Slam titles, on Sunday night — a 6-4, 6-2, 6-2 victory over Bernard Tomic that moved him into the quarterfinals for a 31st consecutive major.
Federer's quarterfinal will be his 1,000th tour-level match. He plays 2009 U.S. Open champion Juan Martin del Potro, whom he once expected to rise to No. 1.
Rafael Nadal advanced with a convincing win over fellow Spaniard Feliciano Lopez. The 2009 champion's right knee was heavily wrapped and his left ankle needed to be taped after three games of the first set. Afterward, he said he was fine.
He will play Tomas Berdych, hoping to avoid a third consecutive quarterfinal loss in Melbourne.