Lleyton Hewitt has breezed into the second round of the Delray Beach Open with a win over American Bradley Klahn.
Hewitt, who now has 598 ATP match wins, will next face fellow Australian Marinko Matosevic, who downed Belgian David Goffin 6-2 6-4.
Top seed Tommy Haas also won on Tuesday in $US474,000 ($A526,000) ATP event, but Taiwan's Lu Yen-Hsun retired after winning the first set of his match.
World No.12 Haas, a 35-year-old German who won the event in 2006, needed only 55 minutes to eliminate US qualifier Wayne Odesnik 6-2 6-1 while 32-year-old Aussie Hewitt, cheered on by countryman and golf legend Greg Norman, took 65 minutes to oust Klahn 6-3 6-1.
Haas' win secured a second-round match against US qualifier Steve Johnson, who defeated Kazak Mikhail Kukushkin 6-4 6-3.
Taiwan's Lu, meanwhile, who was coming off a retirement due to a neck injury in a Memphis semi-final against Croatian Ivo Karlovic, won his first set 6-4 but retired against Ryan Harrison after the American held serve to open the second set.
Harrison will next meet Russian Teymuraz Gabashvili, who rallied to beat Aussie Matthew Ebden 2-6 6-3 6-2.
South African fourth seed Kevin Anderson, who lives in Delray Beach, reached the second round by fighting back to beat American Tim Smyczek 4-6 6-1 6-3.
Next in Anderson's path is Karlovic, who opened with a 7-6 (7-4) 6-3 victory over Aussie lucky loser Samuel Groth.
