Flavia Pennetta | Entertainment News, Photos, and Videos

Serena Williams may not have won the calendar year Grand Slam as hoped, but she is taking the high road by congratulating Flavia Pennetta, the winner of the 2015 U.S. Open.

The 33-year-old tennis player was defeated in the semi-finals round yesterday in a major upset after Italian player Roberta Vinci pulled off a surprise victory.

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Had she won the tournament, Serena would have made history as the first tennis player, male or female, to win a Grand Slam since Steffi Graff did in 1988.

Check out Serena‘s thoughtful tweet…

Flavia Pennetta has won a grand slam title after being crowned the winner of the Women’s Singles tournament at the 2015 U.S. Open Championships on Saturday (September 12) in New York City.

The 33-year-old Italian player, pictured right, defeated her best friend Roberta Vinci in the finals.

The two players, who were long shots to make it to the finals, made history as this was the first time that two Italian players have faced off in the final round of the U.S. Open. What makes the story even better is that the players have known each other since they were 10!

Roberta pulled off a major upset yesterday by defeating Serena Williams and ending her bid for the complete grand slam win.

While accepting her trophy after the match, Flavia announced that she is retiring and this is her final match.