Defending champion Ryan Sweeting and Houston resident Michael Russell advanced to the second round at the U.S. Men's Clay Court Championship on Tuesday.

Sweeting was a surprise winner here a year ago when he beat Japan's Kei Nishikori in the finale, in his debut appearance in an ATP World Tour final. On Tuesday, the American completed a 6-3, 7-6 (8-6) victory over Brazilian Ricardo Mello, using six aces and saving 7-of-9 break point opportunities to complete the victory in 108 minutes at River Oaks Country Club.

American qualifier Russell dropped the first set to Spaniard Daniel Gimeno- Traver before taking the final two for a 2-6, 7-5, 6-1 decision in just under two hours. Russell fought off six aces from his Spanish opponent and advances to face top seed and World No. 9 Mardy Fish, who won this tournament back in 2006, on Thursday.

Fish and American John Isner are this week's top-seeded players.

In other first round action, Russian Igor Kunitsyn dropped Belgian Xavier Malisse 6-4, 6-2, while Italian Paolo Lorenzi came from behind to beat American wild card Wayne Odesnik 6-7 (3-7), 6-2, 6-3. The 26-year-old South African native Odesnik was the Houston runner-up in 2009, which marks his only career ATP World Tour final.

Argentine qualifier Horacio Zeballos made his third straight Houston appearance, defeating Romanian Adrian Ungur 6-3, 6-3 in 90 minutes for the victory. Zeballos advanced to the semi-finals here two years ago.

Both ranked in the World's top 100, Japanese compatriots Tatsuma Ito, ranked No. 98, and qualifier Go Soeda, ranked No. 77, battled in the first round, with Ito taking a 6-4, 7-5 decision in 1 hour, 51 minutes.

The winner of this $442,500 event will take home $79,880.