Today in U.S. Open: Quarterfinals Continue With Azarenka, Wawrinka and Federer

9-9-15 Venus and Serena Williams
Venus Williams of the United States greets sister Serena Williams of the U.S. after their match on day nine of the 2015 U.S. Open tennis tournament at USTA Billie Jean King National Tennis Center, September 8, 2015. Jerry Lai/USA TODAY Sports/Reuters

The U.S. Open continues full steam ahead Wednesday with the last of the singles tournament quarterfinals. Only four men and four women will be left standing at the end of the day to advance to the next set of matches, which could earn them a spot in the finals.

Tuesday saw No. 43 seed Roberta Vinci of Italy defeat Kristina Mladenovic of France and Croatia's Marin Cilic beat France's Jo-Wilfried Tsonga. Later in the day, the No. 1 seeds in both the men's and women's tournaments took the court.

Serena Williams faced and defeated her sister, Venus, to advance to the semifinals and bring her one step closer to a calendar grand slam. If Serena wins two more matches to take the U.S. Open, she'll be the first to win all four major tournaments in one year since Steffi Graf did the same in 1988. She'll play her next match against Vinci. In the men's, Serbia's Novak Djokovic prevailed over another Spanish opponent, Feliciano Lopez, to advance to the semifinals, where he'll face Cilic.

The quarterfinals continue on Wednesday at 11 a.m. with Petra Kvitova of the Czech Republic taking on Flavia Pennetta of Italy, Belarus's Victoria Azarenka facing Romania's Simona Halep, and Switzerland's Stan Wawrinka playing South Africa's Kevin Anderson, who upset No. 3 seeded Andy Murray of the U.K. in the previous round.

One last men's singles match rounds out Wednesday's schedule following an exhibition doubles match featuring Jim Courier and Mardy Fish against Michael Chang and John McEnroe. At 8 p.m. or later, No. 2 seeded Roger Federer of Switzerland faces Richard Gasquet of France.

Fans can check the schedule for singles, doubles and juniors matches online, and can watch Wednesday's matches on ESPN or ESPN2, sign in to stream the games online or track scores live online.