MELBOURNE, Australia -- Kim Clijsters moved into an Australian Open semifinal showdown with second-ranked Vera Zvonareva, beating Agnieszka Radwanska 6-3, 7-6 (4) on Wednesday as Air Force planes flew overhead as part of celebrations for the national holiday.
Cannons went off earlier when Zvonareva started the Australia Day proceedings at Rod Laver Arena with a 6-2, 6-4 win over Petra Kvitova.
Thursday's semifinal will be a rematch of the last U.S. Open final, where Clijsters collected her third Grand Slam title.
Clijsters is the only Grand Slam winner into the women's semis, although she's still seeking her first major title outside of America. No. 1-ranked Caroline Wozniacki and China's Li Na meet in the other half of the draw.
"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.
"I lost to Vera at Wimbledon last year, I beat her in finals of U.S. Open," she said.
Clijsters has a 6-3 lead in head-to-heads against Zvonareva, while Li has won two of her three matches against Wozniacki.
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 Royal Australian Air Force "Roulettes" flying overhead, Clijsters converted her fourth break-point chance to tie it at 5 and the set went to a tiebreak.
"I think the planes kind of took me up higher!" joked Clijsters, long a crowd favorite in Australia, where she's still called "Aussie Kim." She was also engaged for a time to former No. 1-ranked Lleyton Hewitt.
"Happy Australia Day everybody," she said in a salute to her supporters.
Clijsters has now reached the semifinals five times in Australia. Her best run remains her trip to the final in 2004, when she lost to fellow Belgian Justine Henin.
Zvonareva wore a black ribbon on her hat in a gesture to send her condolences to 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 sightline 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."
She said it was also difficult to concentrate given the situation in Moscow.
"Definitely the news came and it was quite shocking. It was difficult," Zvonareva said. "You're calling back home and making sure everyone is OK, the people that you know. I just tried to put it away. It is terrible. But you try to move on."