Houston - Japan's Go Soeda survived a scare from former world No 1 Lleyton Hewitt and American Sam Querrey barely broke a sweat in advancing at the US Clay Court Championships on Monday.
Soeda needed two hours and 36 minutes to post a 4-6, 7-6 (7/3), 6-3 win over Hewitt, who won this event in 2009. The 30-year-old Soeda had to save one match point against Hewitt.
He will face either Jeremy Chardy or Dusan Lajovic in the next round.
Querrey advanced after Marinko Matosevic retired from their match after 18 minutes on the court at the River Oaks Country Club.
Querrey, the No 8 seed, was leading 4-1 in the first set when a foot injury caused Matosevic to pack it in. Querrey was the runner-up in Houston in 2010.
Also on day one, Argentine Federico Delbonis beat Lithuanian Ricardas Berankis 6-2, 7-6 (7/5) and Sam Groth, of Australia, toppled Dominican Victor Estrella Burgos 7-6 (7/3), 6-4.
The top seeds in Houston are Spaniards Feliciano Lopez and Roberto Bautista Agut. Lopez's first match is against Groth.
Fernando Verdasco beat back-to-back runner-up Nicolas Almagro in last year's all-Spanish finale.