Flavia Pennetta

(Left): Serena Williams of the United States reacts against Flavia Pennetta of Italy during their women's singles quarterfinal match on Day Ten of the 2014 US Open at the USTA Billie Jean King National Tennis Center on September 3, 2014. (Photo by Chris Trotman/Getty Images for USTA)

(Right): Novak Djokovic of Serbia serves against Andy Murray of Great Britain during their men's singles quarterfinal match on Day Ten of the 2014 US Open at the USTA Billie Jean King National Tennis Center on September 3, 2014. (Photo by Julian Finney/Getty Images)

Serena Williams, Novak Djokovic Off To US Open Semifinals

After a bad-as-can-be start, dropping the first three games, Serena Williams quickly turned things around and stretched her U.S. Open winning streak to 19 matches to get back to the semifinals.

09/03/2014

Kei Nishikori of Japan returns a shot against Stan Wawrinka of Switzerland during the US Open quarterfinals on Sept. 3, 2014. (Photo by Elsa/Getty Images)

Japan’s Nishikori Outlasts No. 3 Wawrinka For Spot In US Open Semifinals

The match went 4 hours, 15 minutes, and the 10th-seeded Nishikori managed to shake off any lingering exhaustion from his previous victory, which lasted 4:19 and ended at 2:26 a.m. Tuesday, equaling the latest finish in tournament history.

09/03/2014

Novak Djokovic (Photo by Matthew Stockman/Getty Images) and Serena Williams (Photo by Chris Trotman/Getty Images for USTA) in action at the 2014 US Open.

Murray-Djokovic, Serena-Pennetta Highlight Busy Wednesday At US Open

Andy Murray went more than a year between victories over top-10 opponents. Now he needs to make it two in a row.

09/03/2014

Flavia Pennetta of Italy returns a shot against Casey Dellacqua of Australia during their women's singles fourth round match on Day Eight of the 2014 US Open at the USTA Billie Jean King National Tennis Center on September 1, 2014 in the Flushing neighborhood of the Queens borough of New York City.  (Photo by Julian Finney/Getty Images)

Serena Thrilled To Finally Make A Grand Slam Quarterfinal In 2014

Serena Williams reached her first Grand Slam quarterfinal of the year with a 6-3, 6-3 victory over Kaia Kenepi in the U.S. Open on Monday, keeping her hopes alive for a third straight Flushing Meadows crown.

09/01/2014

Victoria Azarenka of Belarus plays against Flavia Pennetta of Italy during their US Open women's singles semifinal match at the USTA Billie Jean King National Tennis Center in New York on Sept. 6, 2013. (Photo: TIMOTHY CLARY/AFP/Getty Images)

Azarenka Wins Ugly, Gets Dominant Serena In US Open Final Rematch

Six times, Serena Williams was a single point from winning on Friday. Six times, she failed to come through. All that did, of course, was delay the inevitable.

09/06/2013

Flavia Pennetta of Italy embraces Roberta Vinci at the net after their women's singles quarterfinal match on Day 10 of the US Open at USTA Billie Jean King National Tennis Center on September 4, 2013. (Photo by Elsa/Getty Images)

Azarenka And Nadal Turn Their Games Up, Earn Spots In US Open Semis

Flavia Pennetta made her first Grand Slam semifinal, defeating 10th-seeded Roberta Vinci 6-4, 6-1 on Wednesday in an all-Italian quarterfinal at the US Open.

09/04/2013

Alison Riske (Photo by Elsa/Getty Images)

American Alison Riske Makes US Open Round Of 16

Maybe’s Riske’s incredible run isn’t that much of a surprise considering her recent surge.

08/31/2013

Sara Errani (Photo by Timothy Clary/AFP/Getty Images)

Sara Errani Upset In 2nd Round Of US Open

Flavia Pennetta ousted fourth-seeded Sara Errani 6-3, 6-1 in an all-Italian second-round match Thursday for the biggest upset so far at the US Open.

08/29/2013

Maria Sharapova, Flavia Pennetta (credit: Nick Laham/Getty Images Sport )

Maria Sharapova Out Of US Open; Upset In 3rd Round By Flavia Pennetta

Tennis fans at the US Open witnessed a pretty big upset Friday.

09/02/2011