Hewitt has problem in Houston

The Australian former world number one, champion here in 2009, clinched the first set against his Japanese opponent but lost the second on a tie-break before slumping to a 4-6 7-6 (7/3) 6-3 defeat after two and a half hours.

His countryman Sam Groth had better luck as he edged out Victor Estrella Burgos 7-6 (7/3) 6-4 but another Australia, Marinko Matosevic, retired early to send eighth seed Sam Querrey through as a 4-1 winner.

In the remaining first-round match, Federico Delbonis of Argentina downed Ricardas Berankis 6-2 7-6 (7/5).