Serena Williams (WTA World number 8) has qualified for the quarterfinals of the US Open on Monday.

The third seed defeated the Greek Maria Sakkari (WTA World Number 22) in the Arthur Ashe stadium in three sets 6-3, 6-7 (6/8) and 6-3.

The 23-time Grand Slam champion had her revenge on Sakkari who defeated her at the quarters of the Western & Southern Open 5-7, 7-6 (7/5) and 6-1.

In New York, Serena Williams is aiming for a 24th grand slam title in the ankle, more than equal to record holder Margaret Court.

Williams has already won the US Open six times (1999, 2002, 2008, 2012, 2013, 2014), the past two years she was killed in the final.

Meanwhile, Tsvetana Pironkova has qualified for the quarterfinals of the US Open for the first time in her career.

The Bulgarian took it on Monday after a three-setter from the French Alizé Cornet (WTA 56): 6-4, 6-7 (5/7) and 6-3. The 32-year-old Pironkova is not classified.

After more than three years of absence from the track, a period in which she gave birth to her son Alexander, she is making her comeback at the US Open.

Pironkova, ten years ago semi-finalist at Wimbledon, now meets 23-time grand slam champion Serena Williams (WTA 8) for a place in the semi-finals.