NEW YORK (AP) - Roberta Vinci planned to watch the Williams sisters play in the U.S. Open quarterfinals Tuesday night. She wasn't rooting for one or the other.
''Doesn't matter,'' she said with a wide grin. ''I am in the semifinal.''
For the first time in a major, at the age of 32.
Facing an opponent a decade younger, the Italian outlasted Kristina Mladenovic 6-3, 5-7, 6-4 on Tuesday afternoon. She will face Serena Williams next after her 6-2, 1-6, 6-3 victory over Venus.
With Vinci's ranking down to 43rd, she never expected this. This is her 44th Grand Slam tournament. Only Elena Likhovtseva had played in more (46) before making her semifinal debut at the 2005 French Open.
Vinci recognizes she's had a favorable draw - she has yet to meet a seeded opponent. Two top-10 players she could have faced - Ana Ivanovic and Carla Suarez Navarro - were upset; another, Maria Sharapova, pulled out because of injury.
In the fourth round Sunday, Vinci was scheduled to take on 25th-seeded Eugenie Bouchard, but the Canadian withdrew after sustaining a concussion when she slipped and fell in the locker room two days earlier.
''Maybe this was my tournament,'' Vinci said.
That left her plenty rested for Tuesday's match on a steamy afternoon. Mladenovic, in contrast, didn't wrap up her fourth-round win until 1 a.m. Monday, and then she played doubles later that day. She struggled with cramping Tuesday, when trainers rubbed ice on her legs during changeovers in the final two sets.
Still, the 40th-ranked Frenchwoman rallied from down a break in the second to force a third. At 3-3 in the decisive set, the two played a 15-minute game with 10 deuces. Mladenovic had six game points she failed to convert.
''That was a mental massacre for both of us,'' Vinci said.
After getting broken, Mladenovic asked for a medical timeout. Not eligible under the rules to receive more treatment for cramping, she said it was a different injury. Vinci protested to the chair umpire as Mladenovic had her left thigh wrapped.
It wouldn't make a difference. Mladenovic repeatedly bent over in discomfort between points, and Vinci won her last two service games to clinch victory after 2 hours, 32 minutes.
Mladenovic, who had never been past the third round at a major before now, had 64 unforced errors, including 11 double-faults - many of them at key moments.
''Of course a lot of positives for me with entire tournament,'' she said. ''Even today if I lost, it was quite a great and big battle out there with Roberta.''
Vinci has played on the biggest stages before, winning five major doubles titles with former partner Sara Errani. She had been 0-2 in Grand Slam singles quarterfinals, both at the U.S. Open.
''Of course I think I'm at the end of my career, so my semifinal, first semifinal, it's incredible,'' she said. ''When you work hard for a long time and every single day, sometimes you have some periods down and try to come back. It's not always easy.
''But it's nice. I'm very proud of myself.''