BREAKING: Serena Williams beats sister Venus in the U.S. Open to advance to semifinals

Serena Williams defeated older sister Venus in three-set victory  6-2, 1-6, 6-3 on Tuesday night, to move to semifinal match against Italian Roberta Vinci, 32,  and ranked world No 43.

The 33-year-old World No. 1 tennis ace is now two wins away from the elusive calendar Slam.

Serena on Venus - "It's a really great moment. She is the toughest player I've played in my life and she is the best person I know. I'm going against my best friend and the greatest competitor in women's tennis, in my mind, so it is a tough day. When I'm playing her I don't think of her as my sister, when we're in the moment you don't really think about it. We've trained all our lives for these moments and it is a great honour to play in front of everyone here. Holding serve in the third set was huge - she came out blasting and I was defending a lot. She has so much power so it was tough."