Serena Williams weathered a barrage of big serves and heavy groundstrokes early and needed nine match points before beating Madison Keys, 7-6 (5), 6-2, to set up an Australian Open final against second-seeded Maria Sharapova.
Top-ranked Williams, bothered by a cold in recent days, dominated the second set of the all-American semifinal, breaking Keys' serve twice. Williams' semifinal win ensured she will retain the top ranking, regardless of the outcome of the final.
On the men's side Wednesday night, Novak Djokovic was overpowering as he beat Canadian Milos Raonic, 7-6 (5), 6-4, 6-2, in two hours, never facing a break point. The four-time champion, who has dropped his serve only once through five matches, will match up against defending champion Stan Wawrinka on Friday.
In the other men's semifinal, sixth-seeded Andy Murray beat No. 7 Tomas Berdych 6-7 (6), 6-0, 6-3, 7-5 in a semifinal littered with flashes of anger Thursday night. Murray, winless in his previous three appearances in the Aussie Open final, will face either Djokovic or defending champion Stan Wawrinka.
The 19-year-old Keys, playing in her first Grand Slam semifinal, saved seven match points on serve in a penultimate game that lasted more than 11 minutes. Williams kept her cool, wasting one match point on her serve before closing with an ace to reach her 23rd major final.
"She pushed me really hard the first set and I had to really dig deep mentally to get through that," Williams said, pausing to cough. "It was a little frustrating, I had like nine or 10 match points and couldn't close it out. That doesn't happen so much. She played like she didn't have anything to lose."
Sharapova, who beat No. 10-seeded Ekaterina Makarova, 6-3, 6-2, in an all-Russian semifinal earlier Thursday to reach her fourth Australian Open final, has lost her last 15 head-to-head matches to Williams. Her only two wins in their 18 career meetings were at Wimbledon and the tour-ending championship in 2004.
"I think my confidence should be pretty high going into a final of a Grand Slam no matter who I'm facing and whether I've had a terrible record, to say the least, against someone," Sharapova said. "It doesn't matter. I got there for a reason. I belong in that spot. I will do everything I can to get the title."
Williams, an 18-time major winner, is back in the final at Melbourne for the first time since winning her fifth Australian Open title in 2010.
The 33-year-old American said she was nervous at the start, and it showed. Keys broke her serve to open and dictated many of the longer rallies with her heavy ground strokes, forcing Williams to defend more than usual. Keys, who beat Venus Williams in the quarterfinals to reach a Grand Slam tournament semifinal for the first time, had control until she was broken in the sixth game.