Kerber continued her winning streak at the US Open on Sunday night, beating the world's No. 16 player, Petra Kvitova 6-3, 7-5 in just just over two hours. This moved the German into the quarterfinals and increased the pressure on Serena Williams, who now needs to reach the final at Flushing Meadows if she is to prevent Kerber from snatching away her No. 1 ranking.

If Williams does get to the final, she will have the chance to win Grand Slam title number 23, beating the record (22) she currently shares with Steffi Graf. If the American manages to hold onto her No.1 ranking, she will also beat Graf's record of 186 weeks in the top spot.

After Sunday's match Kerber acknowledged that she was conscious of what she may be on the verge of achieving.

"When I was a kid, of course I was dreaming of winning Slams and being one day No. 1, and now it can happen," Kerber said.

"But I'm trying not to put pressure on myself, because I know I have to win a few more matches before I can be the No. 1. When it happens it will be an amazing feeling."

Kerber's next match is against last year's surprise runner-up, Roberta Vinci of Italy.

Williams will look to punch her ticket to the quarterfinals when she faces 52nd-ranked player Yaroslava Shvedova of Kazakhstan.

pfd/jh (SID, dpa, Reuters, AP)