Serena Williams of the U.S.
Serena Williams of the U.S. reacts after losing a point in her quarterfinals match against her sister and compatriot Venus Williams at the U.S. Open Championships tennis tournament in New York, September 8, 2015. Reuters/Carlo Allegri

Serena Williams of the United States continue her quest for a calendar slam and will meet Roberta Vinci of Italy in the semifinals of the 2015 US Open on Thursday (Friday morning in Australia). A win by the American will put her on the verge of matching Germany’s Steffi Graf’s feat of winning four Grand Slam titles in a single year.

Williams, who beat sister Venus, 6-2 1-6 6-3 in the quarterfinals, is not about to overlook her Italian opponent in the final four.

“I'm not going to underestimate her. She played really well. She's not in the semifinals of a Grand Slam for no reason. She knows what to do and she knows what to play,” Williams said via the tournament’s official website when asked about Vinci, who has yet to win in four matches against her in past meetings.

Meanwhile, Vinci knows the tough task ahead in going up against the World No. 1 and the sports most dominant player.

“Yeah, I know that I have a lot of experience, but when you play against Serena doesn't matter. You have to play better then better then better,” Vinci said after her quarterfinals win over Kristina Mladenovic of France in three sets, 6-3 5-7 6-4.

Vinci, who is appearing in her first semifinals appearance in any Grand Slam tournament in her career, has survived her last three matches via three-setters. In four career matches versus Williams, Vinci has also yet to win a set against the American with their last meeting coming this August at the Rogers Cup where Williams won, 6-4 6-3.

Williams is trying to duplicate the achievement of Graf, who won all four Grand Slam tournaments in 1988.

Catch the 2015 US Open semifinals Williams vs. Vinci live streaming via ESPN or the US Open website.

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