MELBOURNE, Australia — For Serena Williams, it's two Russians down, one to go.

Calm, collected and cool — with the Rod Laver Arena roof closed to keep out Melbourne's oppressive heat wave — the second-seeded American ended Olympic champion Elena Dementieva's 15-match winning streak with a 6-3, 6-4 victory Thursday to reach the Australian Open final.

All that stands between her and a 10th Grand Slam title is third-seeded Dinara Safina, who is hungry to take home her first major trophy to go along with the two that brother Marat Safin has earned. Safina ousted fellow Russian Vera Zvonareva 6-3, 7-6 (4) in the other semifinal. The winner Saturday also will rise to the No. 1 ranking.

Second-seeded Roger Federer, seeking a record-tying 14th Grand Slam championship, was playing No. 7 Andy Roddick in the first men's semifinal Thursday night, with No. 1 Rafael Nadal meeting fellow Spaniard Fernando Verdasco on Friday.

Williams has a history of winning here in odd-numbered years — 2003, 2005 and 2007 — but there was nothing odd about her victory.

She followed her traditional pattern of playing her way into form after struggling in her previous matches. She twice faced match points and benefited from fourth-round opponent Victoria Azarenka retiring sick after winning the first set, and got a chance to recuperate when the roof was closed due to the heat Wednesday after she'd lost the first set in the quarterfinals against Russia's Svetlana Kuznetsova.

"I'm excited that I'm playing really consistent," Williams said. "This whole Australia swing, I was just really struggling with my form, for whatever reason, 'cause I definitely put in the time, but it just didn't come together."

It certainly did against Dementieva, who beat her in their last three meetings and was coming off consecutive titles at two warm-up tournaments.

"I think she was very powerful today," the fourth-seeded Russian said. "I think I was maybe not aggressive enough and maybe I was playing not deep enough, which allowed her to be very aggressive and dictate the game."

Both players were happy to have the stadium's retractable roof closed. Outside, the temperature hit 112 degrees — news reports said it was Melbourne's hottest January day since 1939 — and there were plenty of empty seats as some people apparently decided that even getting to Melbourne Park was too much of an ordeal.

Safina has yet to win a major, losing the 2008 French Open final to Ana Ivanovic in her best previous run. She lost to Williams in last year's U.S. Open semifinals.

Her older brother won the Australian title in 2005, the day after Williams beat then-No. 1 Lindsay Davenport in the women's final.

Safina was looking forward to giving him a belated birthday present. Safin turned 29 on Tuesday.

"Maybe now I have some money to buy him a present," she joked. "It's great that I can follow his steps. He was my idol. He's still my idol."

Williams, the reigning U.S. Open champion, found her rhythm quickly against Dementieva, who has not progressed past the semifinals at a Grand Slam since 2004.

While it was cooler inside than out at Melbourne Park, Williams already had soaked through her blue dress by the time the second game was over, not surprising since they had played 16 minutes.

When Williams blasted a clean crosscourt winner while serving at 3-3, she gave Dementieva a long glare. Dementieva smacked a service return winner on the next point and glared right back.

Dementieva held serve to start the second set in a game that went to deuce five times and lasted 14 minutes, then broke Williams en route to a 3-0 lead.

That sparked a four-game run for Williams until Dementieva broke to even the second set at 4-4.

Then nerves seemed to get the best of Dementieva. Having problems with her service toss, she double-faulted twice, the second setting up break point. Williams ripped a backhand winner down the line and pumped her fist.

Williams has been having problems with her first serve, but it came through when she needed it most. Serving for the match at 5-4, she started with an ace and hit another serve that Dementieva sent long.

At 30-15, Williams followed with another ace. Dementieva squealed and bent over in frustration. Another powerful serve on match point set up an easy overhead and it was over in 98 minutes.

But Williams' day wasn't finished and she went on to partner with sister Venus in a women's doubles match. Seeking their eighth Grand Slam title together, they routed Australia's Casey Dellacqua and Italian Francesca Schiavone 6-0, 6-2 to reach the final.