WASHINGTON (AP) _ Eighth-seeded Andy Murray of Britain advanced to the third round of the Legg Mason Tennis Classic on Wednesday, beating Paraguay's Ramon Delgado 6-4, 6-3 in 100-degree heat.

Murray, who had 13 aces, took command in the sixth game of the first set, firing two aces to take a 4-2 advantage, then cruised to victory in the hot conditions.

``You have to try and finish the points a little quicker than normal,'' Murray said. ``It's so hot out there, that it's tough to catch a break with points. It's just so humid out there.''

In other second-round action Wednesday, 16th-seeded American Mardy Fish beat Tomas Zib of the Czech Republic 6-4, 6-4 to set up a match against Andrea Stoppini, the Italian who upset five-time champion Andre Agassi on Tuesday.

Also, Jan-Michael Gambill, a lucky-loser replacement in the main draw after second-seeded Andy Roddick withdrew because of a back injury, beat Janko Tipsarevic of Serbia 2-6, 6-3, 6-0. Germany's Denis Gremelmayr beat 13th-seeded countryman Bjorn Phau, 6-4, 6-3, and Dmitry Tursunov of Russia advanced when Edgardo Massa of Argentina retired with the match tied 3-3 in the third set.