Federer, the defending champion, was tested in the first set before winning his first match since capturing his fourth straight U.S. Open on Sept. 9. His only competition since the Open were two singles matches in the Davis Cup.

"I took a rest so I could be 100 percent here, and now I'm fresh and eager to play here again," said Federer, who hasn't lost to an American in four years, a streak of 39 matches.

The top-ranked Swiss will play the winner of Wednesday's match between Argentines Agustin Calleri and 13th-seeded Guillermo Canas. Calleri advanced after rallying for a 3-6, 7-6 (4), 6-4 win over Dimitry Tursunov.

David Nalbandian and Ivo Karlovic won first-round matches while Nikolay Davydenko withdrew because of an injured right elbow. Nalbandian rallied past Arnaud Clement 5-7, 6-2, 6-4, and Karlovic served 17 aces in beating Marat Safin 6-3, 6-4. Karlovic, 6-foot-10, had one serve that reached 136 mph.

Davydenko, seeded fourth, said his injury made it "too dangerous" for him to play this week. He will fly to Germany on Wednesday for therapy in an attempt to play at the St. Petersburg Open. The Russian qualified for the Masters Cup in Shanghai with his Kremlin Cup victory Sunday.

"I try as hard as possible to recover for the next week," he said.

Federer served two consecutive aces to thwart Ginepri's double-break chance in the seventh game of the first set. Ginepri, a 72nd-ranked qualifier, forced Federer into 17 of his 30 unforced errors in the first set as both players held serve to the tiebreaker, which Federer clinched with one of his 10 aces.

In the second set, Federer scored the decisive break in the fifth game, lobbing his return over Ginepri as he came to the net.