Italian veteran Flavia Pennetta announced her retirement immediately after claiming the women's US Open crown in New York on Saturday.

Pennetta had just beaten countrywoman Roberta Vinci 7-6 (7-4) 6-2 in an all-Italian final at Flushing Meadows for her first grand slam title when she revealed the news during an on-court interview.

Fans watched on stunned as the 33-year-old told ESPN: "Before I started this tournament, one month ago, I made a big decision in my life. And this is why I would like to say goodbye to tennis.

"I'm really happy. It's what all players want to do, go home with one of these big trophies. So this one was my last match at the US Open and I couldn't think to finish a better way.

"I want to thank everyone who supported me during my career. All my coaches, my family, who aren't here, but they're going to be proud of me. I love you guys."

It is unclear whether Pennetta will see out the season, though the newly crowned US Open champion reportedly told Eurosport afterwards that she plans to retire at the end of 2015.