US second seed Mardy Fish needed only 20 minutes to reach the second round of the $442,500 ATP Delray Beach International Championships on Tuesday when German rival Bjorn Phau retired.
Fish led 5-0 and had lost only six points in the match, breaking Phau twice before the German halted the match, advancing the American into a second-round meeting with Brazil's Ricardo Mello.
South African fifth seed Kevin Anderson rallied to beat US lucky loser Donald Young 6-7 (5/7), 7-6 (7/4), 6-2 after two hours and 30 minutes, booking a second-round match against Frenchman Florent Serra.
Serbian sixth seed Janko Tipsarevic also advanced, winning an epic marathon tie-breaker and a lopsided one to eliminate Ivo Karlovic 7-6 (16/14), 7-6 (7/1) despite 18 aces from the Croatian, who lost in last year's Delray Beach final.
Tipsarevic will next face Slovenian qualifier Blaz Kavcic, who eliminated Colombia's Robert Farah 6-1, 6-4.
Japan's Kei Nishikori also opened with a victory, downing Argentina's Brian Dabul 6-2, 7-6 (7/5). He will next face US wild card James Blake, who ousted German seventh seed Benjamin Becker on Monday.
Croatia's Ivan Dodig also reached the second round, dispatching Russian Igor Kunitsyn 6-4, 2-6, 6-3. Dodig will face the winner of a later match between Israel's Dudi Sela and Australian qualifier Marinko Matosevic.
Matosevic replaced US top seed Andy Roddick in the 32-man draw when the American pulled out Monday, citing illness after a three-set Memphis final struggle before capturing his 30th career ATP title.
Latvian Ernests Gulbis, the 2010 Delray winner, is playing in Dubai this year.