STANFORD -- Serena Williams still has her 61st career title to win Sunday, but any questions about her health, stamina and resolve after her much-dissected Wimbledon wilt a month ago already have been answered.
Serena's not only back, but she's back with a vengeance and a point to prove.
Playing her second tough match in a span of 20 hours at Taube Family Tennis Center, Williams withstood a stiff early challenge from No. 8 seed Andrea Petkovic of Germany and ultimately cruised to a 7-5, 6-0 victory in the Bank of the West Classic semifinals Saturday.
Angelique Kerber, the third-seeded German who had to rally from near straights-set defeat to oust Varvara Lepchenko 4-6, 7-6 (4), 6-2 in the other Saturday semifinal, stands in the way of Williams winning for the third time in a row at this event in which she's appeared (she skipped 2013) and No. 61 all-time as a professional.
Williams made no bones about the fact that winning the Bank of the West, her first tournament since her Wimbledon woes, would be special in light of all the whispers and speculation about what might have happened to her in England, which she has maintained was the result of a viral infection.
"It would mean a lot to me because of that and just trying to get back on the right track," Williams said.
She looks as if she's already there. She survived a grueling three-set battle with Ana Ivanovic on Friday night but played some of her best tennis at the end of that match. That pattern was even more dramatic Saturday afternoon, when Williams and Petkovic held serve for the first 11 games against each other, but Serena found a higher gear and broke her opponent to win the first set, then registered a bagel in the second.
Williams' only test in the second set came while serving the third game ahead 2-0. She engaged in a wild, exhausting 19-stroke rally with Petkovic and lost the point when she slammed a fairly easy overhead into the net. Both players bent over to grab their breath.
"The point was crazy," Petkovic said. "I don't know how she felt, but I really felt my hamstrings afterward."
"I was so distraught, because I really should have won that point," Williams said. "I was on the defensive and somehow managed to come back, then I finally got an easy shot, and I missed it. But it still felt good. I like playing long points like that, because it really tests your fitness and where you are and how you will react after that."
Williams reacted by overcoming Petkovic's only break point chance of the match and pulling out the game for a 3-0 lead. From there, it was only a question whether Serena would pitch the second-set shutout, which she did.
Petkovic, 26, beat Venus Williams in the semifinals Friday and was trying to become the ninth woman to beat both Williams sisters in the same tournament. She knew she was in trouble when she was broken to end the first set, and despite her second-set thumping, still walked away smiling that she got to play her two idols while growing up.
"Playing one of them is a lot, but playing two of them in a row, it was so weird," she said. "I had a laughing fit yesterday just thinking about playing them both in a row. For me, it was like a video game, because they are two of the best tennis players ever."
In the other semifinal, the unseeded Lepchenko, a 28-year-old Uzbek-American ranked 59th in the world, had a golden chance to reach a WTA final for the first time in 170 events since turning pro in 2001. She won a hard-fought first set and was leading 5-2 in the second set. But Lepchenko couldn't close the deal, even though she had match point serving at 5-4 and led the tiebreaker 4-2 before Kerber reeled off five straight points to force a third set.
The 26-year-old Kerber, ranked eighth in the world with one win over Serena in four career meetings, finally took control of the 2 hour, 39 minute match in the third set by holding all of her service games while breaking Lepchenko twice, including the final game.
Kerber, who has three career WTA titles, will be playing in her fourth final this year but is still looking for her first victory.
Follow Carl Steward on Twitter at twitter.com/stewardsfolly.
No. 1 Serena Williams d. No. 8 Andrea Petkovic 7-5, 6-0
Angelique Kerber d. Varvara Lepchenko 4-6, 7-6 (4), 6-2
Williams v. Kerber, 2 p.m. ESPN2