Melbourne, Australia — Serena Williams weathered a barrage of big serves and heavy groundstrokes in the first set before beating 19-year-old Madison Keys 7-6 (5), 6-2 to set up an Australian Open final against Maria Sharapova.
Williams dominated the second set of the all-American semifinal, breaking Keys' serve twice. Keys saved seven match points on serve in the penultimate game before Williams closed with an ace on her ninth match point.
Sharapova beat fellow Russian Ekaterina Makarova 6-3, 6-2 earlier Thursday.
Williams, an 18-time major winner, is back in the final here for the first time since winning her fifth Australian title in 2010.
The win ensured Williams will retain the top ranking, regardless of the outcome against No. 2 Sharapova. The American has a 16-2 record against Sharapova, including the last 15.
The second-ranked Sharapova needed 10 minutes to hold in her opening service game, fending off two break points. She responded to the only service break against her in the first set by winning six straight games and seizing control of the match from the 10th-seeded Makarova, who had only taken one set off her in five previous matches.
She will next meet the winner of the all-American semifinal between top-ranked Serena Williams and 19-year-old Madison Keys.
Sharapova won the Australian Open title in 2008 but was subsequently comprehensively beaten in championship matches in 2007, by then unseeded Serena Williams, and in 2012 by Victoria Azarenka.
The five-time major winner opened the 2015 season in confident style by winning the Brisbane International title but had a close call in the second round here, having to save match points against No. 150-ranked Russian qualifier Alexandra Panova. Since then, she hasn't faced a set point.
"It's been a strange road for me to get to the finals, but I'm happy," said Sharapova, who is into her 10th Grand Slam final. "Came from behind in a few, really behind in one — saving match points. I felt like I was given a second chance. I just wanted to take my chances."