The decision by Andy Roddick and Mardy Fish to pass on the trip to Bejing in order to prepare for the U.S. Open seems to be paying off.

Fish beat Frenchman and French Open semifinalist Gael Monfils in straight sets Monday, to become the first man in the quarterfinals. Earlier he beat friend James Blake in three straight sets in the third round. Blake did travel to China where he finished fourth and missed a medal in the Olympics despite beating Roger Federer and having three match points to get to the final round and ensure himself of a silver.

Roddick has dropped only one set in his first three rounds, and on Tuesday will have the chance to join Fish in the quarters if he can get past Fernando Gonzalez. Gonzalez was the silver medalist in Bejing, and won a controversial match there over Blake in the semis in which it seemed to many — especially Blake — that on match point Gonzalez touched a ball that went out. The call went against Blake, despite his protestations. You can be sure Roddick would like to get even for his fellow Davis Cup teammate.

The road beyond the quarters gets very tough for both Americans. Fish next plays this year’s worldbeater, Rafael Nadal, (although Nadal looked tired and only slightly above average in his win against Sam Querrey); Roddick, if he beats Gonzalez, is on track to meet No. 3 seed Novak Djokvic.

If either Roddick or Fish advance to the semis, they will become the first American man to reach the final four of a Grand Slam this year. Blake’s run to the quarters of the Australian Open was previously the best performance in a major by an American in 2008.