The No. 26 seed Flavia Pennetta is the highest seeded woman to reach the U.S. Open final since Serena Williams, who was the No. 28 seed when she was runner-up to Samantha Stosur in 2011.

Both finalists will be in their 30s. Pennetta is 33, about five months younger than Williams and a year older than Williams’s opponent, Roberta Vinci.

Pennetta defeated Simona Halep in only 59 minutes, her shortest match of her tournament. She collected 23 winners to Halep’s 10. She broke Halep six times.

Pennetta is 0-7 in her career against Williams. Their last match, in Toronto in August, went three sets. Pennetta is 5-4 against Vinci, but they have not played since a 2013 U.S. Open quarterfinal, won by Pennetta.

The U.S. Open is the only Grand Slam event in which Pennetta has advanced past the quarterfinals in her career. This year she lost in the first round at the Australian Open and Wimbledon and in the round of 16 at the French Open.