Second-round play at the U.S. Men's Clay Court Championship was scheduled to start Wednesday, but rain forced all four matches to be postponed until Thursday.
One second-round match got underway, as seventh-seeded Italian Paolo Lorenzi led compatriot Flavio Cipolla 3-2 before the rain started at River Oaks Country Club.
Top-seeded Nicolas Almagro was slated to face Gael Monfils, while second- seeded Tommy Haas, who captured this tournament back in 2004, was scheduled to take on Ricardas Berankis.
John Isner, last year's runner up here, also had his second-round match pushed back to Thursday, when the fifth-seeded American will take on wild card Jack Sock.
Four second-round matches were already on Thursday's slate, highlighted by third-seeded Juan Monaco, who topped Isner in last year's final, opening defense of his Houston title against American Tim Smyczek.
The first round concluded with a pair of matches before the rain started, as Spaniard Ruben Ramirez Hidalgo handled Indian Somdev Devvarman 7-6 (7-5), 6-0 and fading former world No. 1 Aussie Lleyton Hewitt succumbed to 94th-ranked Argentine Martin Alund 4-6, 6-3, 6-1. The two-time Grand Slam champion Hewitt was the Houston titlist four years ago.
The 2013 Houston champ will collect $82,300.