Tenth-seeded Mardy Fish reached the quarterfinals of the Western & Southern Open with a 6-3, 6-3 win over Radek Stepanek on Wednesday.

Fish, a two-time runner-up at this event, beat his Czech Republic opponent for the first time in five career matches, including three straight-set losses. Fish celebrated his win with a leaping right fist pump after Stepanek's backhanded drop shot hit the net on match point.

The American hasn't dropped a set and has been broken only once while rolling into the quarterfinals.

Germany's Angelique Kerber became the first player to reach the quarterfinals. The No. 5 seed needed to win a tiebreaker to advance with a 6-4, 7-6 (5) win over qualifier Andrea Hlavackova of the Czech Republic.