Ivanovic raced to a 5-0 first set lead before closing the set out 6-1. But after committing 19 unforced errors to lose set two 6-4, Ivanovic also lost the first game of set three. At 3 all however in the final set, Ivanovic broke serve before holding her own serve at love to set up the 6-1, 4-6, 6-4 win.

"It's going to help me, because it was very challenging," said Ivanovic. "I just dropped my concentration for a moment, and then it was very hard for me to get back in the game. So, yeah, definitely, a match like this is going to help me in the next rounds."

Later in the afternoon 4th seeded Serena scored a 6-1, 6-4 win versus Kateryna Bondarenko of the Ukraine, while 7th seeded Venus routed Australia’s Samantha Stosur 6-2, 6-3. Venus took the US Open title in 2000 and 2001 while Serena won one year earlier in 1999 and also in 2002.

Six of the top seven players of the WTA Tour could claim the world's number one ranking after the US Open concludes. World number five Maria Sharapova of Russia is absent with a shoulder injury. But Ivanovic, Serena, Jelena Jankovic of Serbia, Svetlana Kuznetsova, Elena Dementieva and Dinara Safina all of Russia stand a chance to score enough rankings points with a title to move into the top spot.

Ivanovic, Jankovic or Serena will become number one if either player takes the title. However Kuznetsova, Jankovic and Safina would need to win the title and hope Serena, Ivanovic, and Jankovic all lose in the early rounds.