MELBOURNE, Australia (AP) Andy Murray, Kim Clijsters and Vera Zvonareva found themselves in familiar territory late in a Grand Slam tournament on Wednesday.

Murray beat unseeded Alexandr Dolgopolov 7-5, 6-3, 6-7 (3), 6-3 at the Australian Open to advance to the semifinals and a possible match against Rafael Nadal, the player he beat last year in the quarterfinals.

That was the last time Nadal lost at a major.

So there's more at stake for Nadal this time - he's trying to become the first man since Rod Laver in 1969 to win four straight majors. Nadal, who won last year's French Open, Wimbledon and U.S. Open tournaments, took on fellow Spaniard David Ferrer in a quarterfinal later Wednesday.

Clijsters, the growing favorite in the women's draw, advanced to a semifinal against No. 2 Zvonareva, whom she beat in the final at the U.S. Open last September. It will be the 10th tour meeting for the pair, with Clijsters holding a 6-3 advantage.

Clijsters had some nervous moments in her 6-3, 7-6 (4) win over No. 12 Agnieszka Radwanska. None were as bad as when some air force planes flew in formation overhead as part of celebrations for the Australia Day national holiday. Cannons went off earlier when Zvonareva started the Australia Day proceedings with a 6-2, 6-4 win over Petra Kvitova.

Top-seeded Caroline Wozniacki plays Li Na of China in another semifinal Thursday, while defending champion Roger Federer takes on third-seeded Novak Djokovic in a men's semifinal.

Dolgopolov had already beaten 2008 runner-up Jo-Wilfried Tsonga and French Open finalist Robin Soderling and has the kind of unorthodox game that can unsettle higher-ranked players.

Apart from the second set, when 2010 finalist Murray didn't lose a point on serve until he had triple set point, momentum swung frequently.

It was very tough,'' Murray said.He hits the ball different from everyone else.''

Dolgopolov was able to mix up his slice and spin with deep flat shots, sometimes at the net, sometimes at the baseline, and rarely giving Murray a look at the same ball twice in a row.

Dolgopolov had 77 unforced errors, mainly because he was trying to push Murray to the extremes. In the first set, it took Murray more than 10 minutes and four set points to finally win the 12th game.

He got the better of Murray in a 36-ball rally in the third set, saving three break points and then going on to force a tiebreaker.

Dolgopolov's coach, Australian Jack Reader, left the court after the third set and returned asking ``What's going on?'' when Murray had opened up a 3-0 lead in the fourth. From then, although he dropped a serve, Murray was able to remain consistent enough to win it.

Clijsters is the only Grand Slam winner into the women's semis, although she's still seeking her first major title outside of America.

I hope the experience can help me a little bit,'' Clijsters said.But there are some tough players out there, we have Nos. 1, 2, 3 still in and Li Na has been playing really well. So it is going to be really tough.

Zvonareva has lost the last two Grand Slam finals, to Clijsters in New York and Serena Williams at Wimbledon.

Clijsters was up a set and a break before Radwanska rallied, winning three straight games to lead 5-4 with a chance to serve for the second set.

With six planes from the Royal Australian Air Force's aerobatic team, the Roulettes, flying overhead, Clijsters converted her fourth break-point chance to tie it at 5 and the set went to a tiebreaker.

I think the planes kind of took me up higher!'' joked Clijsters, long a crowd favorite in Australia, where she's still calledAussie Kim.'' She also was engaged for a time to former No. 1-ranked Lleyton Hewitt.

Zvonareva wore a black ribbon on her hat in honor of the 35 victims of the suicide bombing at a Moscow airport this week. Her quarterfinal also featured a couple distractions.

Zvonareva and Kvitova were surprised when cannons went off in a nearby park. And Zvonareva asked that the match be stopped for a few minutes while a woman in her sight line was given medical attention in the stands, but chair umpire Mariana Alves told them to continue.

I didn't know they were going to start this noise during our match, it was a difficult moment,'' said Zvonareva, who led the final set 3-0 before the disruptions but saw Kvitova level it at 4-4.You're here to play tennis ... I was trying to keep my concentration.''