Juan Monaco beat Gerald Melzer 6-2, 6-7 (3), 6-4 on Monday night in the first round of the U.S. Men's Clay Court Championship.
Monaco won the tournament in 2012. It was Melzer's 2016 Tour debut after winning three Challenger Series titles.
American Denis Kudla also advanced, fighting off Germany's Mischa Zverev 6-3, 6-7 (2), 7-6 (2). South Korean teenager Hyeon Chung squandered a second-set match point, then made short work of Victor Estrella Burgos of the Dominican Republic 6-4, 6-7 (5), 6-0.
Chung, 19, played in just his fifth ATP World Tour main-draw match. Currently ranked 71st, he was named the ATP's Most Improved Player of the Year for 2015.