Top-seeded American John Isner and former champion Tommy Haas were second-round winners Thursday at the Delray Beach International Tennis Championships.
In the final match of the night, Isner posted a 7-6 (7-2), 6-2 victory over Japan's Go Soeda. He will next face Kevin Anderson, the reigning Delray Beach champion.
The sixth-seeded South African battled past Yen-Hsun Lu of Chinese Taipei 6-4, 3-6, 6-3.
Earlier, the oft-injured one-time world No. 2 and second-seeded Haas handled Uzbekistan's Denis Istomin 6-4, 6-1 at Delray Beach Tennis Center.
Haas, who was the titlist here back in 2006, will meet capable Croat Ivan Dodig in the quarterfinals.
Talented Latvian Ernests Gulbis, a qualifier this week, ousted third-seeded American Sam Querrey, 6-4, 4-6, 7-6 (7-4), in 2 hours, 14 minutes. Gulbis was the Delray Beach champion in 2010.
Meanwhile, five-time Delray Beach finalist Xavier Malisse was sent packing on Day 4, as Spanish qualifier Daniel Munoz-De La Nava doused the eighth-seeded Belgian 7-6 (7-3), 3-6, 6-3.
Malisse was the champion here in 2005 and 2007 and runner-up in 1999, 2001 and 2006.
In other second-round action, Dodig topped Russian Evgeny Donskoy 6-3, 7-5, France's Edouard Roger-Vasselin erased 6-foot-10 Croat Ivo Karlovic 6-4, 7-5 and Lithuanian lucky loser Ricardas Berankis overcame American wild card Jack Sock 3-6, 6-4, 6-1. Karlovic was the Delray Beach runner-up to Gulbis three years ago.