Flavia Pennetta was the last Italian standing at a US Open that has celebrated experience after upsetting 10th-seeded compatriot Roberta Vinci in straight sets to reach her first grand slam semi-final today.

The 31-year-old Pennetta's 6-4 6-1 triumph secured her spot in the last four of the year's final grand slam against either second seed Victoria Azarenka or Daniela Hantuchova, who are scheduled to play later.

A US Open record five 30-somethings had reached the last 16, including 30-year-old Vinci, and Pennetta's victory made it at least a trio into the semi-finals.

"I think we just keep playing. Before the career of the woman was shorter, they retired early," Pennetta said about the rise of the 30-somethings at Flushing Meadows.

"It's good to stay physical, in a good way, and play this good tennis at this age. I'm proud of me now."

Hantuchova, 30, of Slovakia is another of the mature set with a chance to advance, while the other semi-final has already been set with defending champion Serena Williams going against fellow 31-year-old Li Na of China.

The good-natured match between the Italian friends who have competed against one another since they were 10 turned into a rout by the second set, which Pennetta raced through in 24 minutes against an error-prone Vinci.

"It was of course a special day for us," said Vinci, who is part of the world number one ranked women's doubles team with fellow Italian Sara Errani, who is still busy defending their US Open doubles title.

"Is a great chance to go to the semi-final. This time she won, but I think that I'm happy, too, about this tournament."