MELBOURNE, Australia — Andy Murray ran off 11 straight games in another dominating performance, overwhelming Jurgen Melzer 7-5, 6-0, 6-3 Saturday to reach the fourth round of the Australian Open.

The fourth-seeded Murray, seeking his first Grand Slam title, had only 10 unforced errors, including just two in the second set, and overcame a brief lapse toward the end. The 21-year-old Scot next faces No. 14 Fernando Verdasco and is on track for a possible semifinal matchup against top-ranked Rafael Nadal, who played later Saturday night.

"I hope I can keep this form up," Murray said. "I'm going to have to play my best every match to have a chance."

Serena Williams wasn't her sharpest, but she hasn't had to be so far. And there were no distractions as she beat overmatched China's Peng Shuai 6-1, 6-4.

Williams, still chuckling about the man who dashed on court minus his trousers during her doubles match Friday, overcame two service breaks in the second set to keep alive her pursuit of a 10th Grand Slam title.

Rafael Nadal advances as well with a straight-sets win over Tommy Haas of Germany.

The top-seeded Nadal beat Haas 6-4, 6-2, 6-2 Saturday and will play Chile's Fernando Gonzalez. The 22-year-old Spaniard is bidding to win his first Australian Open and prevent second-seeded Roger Federer from tying Pete Sampras' all-time record of 14 Grand Slam singles titles.

Constantly confounded by Murray's blend of power, speed and spin, Melzer did get a huge ovation when he rallied from 15-40 to hold while down 3-0 in the third set to end Murray's streak of 11 games. He had double break point as Murray served in the next game, only to see the him rally.

Melzer broke as Murray served for the match at 5-1 and fended off double match point in the next game. But Murray easily held in the next, finishing it off with his eighth ace and getting one step closer to becoming the first British man to win a major since 1936.

Sometimes sprinting to his chair during changeovers, Murray has raced through his first three matches in a combined 4 hours and 15 minutes, thanks in part to a 45-minute effort in the first round match when Andrei Pavel retired with a bad back.

The mood seemed almost subdued as play got under way at Melbourne Park, a day after the streaker and a violent clash between Serbian and Bosnian fans kept security guards busy.

Ethnic violence flared Friday after defending champion Novak Djokovic of Serbia beat Bosnian-born American Amer Delic. A chair-flinging skirmish left a woman injured, three men charged with riotous behavior and 30 people ejected by police.

Williams, who graded herself a "D-minus" after her last match, gave herself a better mark against Peng, who has never gotten past the third round in 16 Grand Slams.

Hitting two-handed from both sides, 41st-ranked Peng is mostly a retriever, so while her defense was annoying to Williams, she had only 12 winners to 29 for the American.

But Williams became increasingly frustrated as she was broken twice early in the second before pulling herself together.

"I started making more errors and then I lost my serve a couple times," she said. "Then I think I put too much pressure on myself. Then, next thing I know, I was down."

Luckily for Williams, that's not necessarily a bad thing.