American Mardy Fish was forced to pull out of the U.S. Open for "health concerns" on Monday afternoon. Fish's withdrawal means that his opponent, top-ranked Roger Federer, moves on to the quarterfinals.
"I regret that I have to withdraw from the U.S. Open for precautionary measures," Fish said in a statement on the U.S. Open Website. "I was reluctant to do so, but am following medical advisement. I had a good summer and look forward to resuming my tournament schedule in the fall."
According to a Yahoo! Sports report, Fish had heart problems earlier this year when he was hospitalized for an elevated heart rate after an event in Miami and underwent a procedure to attempt to correct the issue.
Federer, who has now reached 38 consecutive Grand Slam quarterfinals, will face No. 6 Tomas Berdych in the quarterfinals. Berdych advanced with a 7-4, 6-4, 6-1 win over No. 11 Nicolas Almagro on Monday.
Both early matches at Arthur Ashe Stadium were easy victories for the higher-seeded women. No. 4 Serena Williams beat Andrea Hlavackova without dropping a game, putting her through to the semifinals. No. 12 Ana Ivanovic also advanced, easily beating Tsvetana Pironkova 6-0, 6-4 this morning.
The one match in progress right now is between No. 6 Angelique Kerber and No. 10 Sara Errani with Errani taking the first set 7-6.
For more on the 2012 U.S. Open, check out SB Nation's tennis hub. Head over to the official U.S. Open website for live scores.