Third seed Guillermo Coria eased his way into round three of the Nasdaq-100 Open with a 7-6 6-0 victory over South African Wayne Ferreira. But sixth seed Rainer Schuettler, 10th seed Nicolas Massu and 16th seed Mardy Fish all bowed out.
Lleyton Hewitt, seeded 17 and looking for his third title of the year, beat Sweden's Robin Soderling 6-4 6-2.
Top seed Roger Federer's opening match against Nikolay Davydenko was postponed until Saturday because of rain.
Massu lost 7-6 6-1 to Andre Pavel and Fish went down 6-4 6-4 to Julien Benneteau.
Before the downpour, American veteran Todd Martin reached the third round with a 6-3 5-7 7-5 defeat of 29th seed Jarkko Nieminen.
But Goran Ivanisevic saw his injury problems continue when he withdrew from him second-round match against 32nd seed Rafael Nadal with shoulder pain.
Spanish teenager Nadal won the first set 6-4 when the former Wimbledon champion decided he was unable to continue.
Gaston Gaudio was another seeded casualty, the 30th-ranked Argentine losing 7-6 (7-5) 6-2 to Robby Ginepri of the US.