Defending champion and second seed Lleyton Hewitt of Australia crushed Russian Marat Safin 6-2, 6-1 in the Las Vegas Open first round on Monday.
Hewitt converted four of six break points and won 83 per cent of his first serve points to clinch victory in 58 minutes.
"I knew I was going to have to be on my game from the start," Hewitt told reporters. "I was able to get up that early break in both sets, which is important."
Safin double-faulted three times and made just 40 per cent of his first serve points.
Hewitt became only the second man, after American Andre Agassi, to win the Las Vegas title three times with a straight-sets victory over Austrian Juergen Melzer in last year's final.
Earlier, fourth seed Guillermo Canas of Argentina maintained his perfect record against Thomas Johansson by beating the Swede 6-3, 7-6.
The 30-year-old from Buenos Aires won two break points out of five to seal victory in just over an hour-and-a-half on the Stadium Court.
Canas, sidelined for 15 months for a doping ban before returning to action in September 2006, has never lost to Johansson in three career meetings.
Eighth-seeded Nicolas Kiefer, a finalist in Las Vegas in 2004, fired down eight aces to beat fellow-German Benjamin Becker 6-4, 6-3.
Kiefer, who was sidelined for the first half of last year with a wrist injury, is making his first ATP appearance since losing in the Australian Open first round in January.
In other matches, unseeded American Sam Querrey scraped past Sebastien Grosjean of France 6-2, 4-6, 7-6 and Russian Evgeny Korolev, a surprise semi-finalist last year, beat Argentina's Sergio Roitman 6-4, 4-6, 6-3.
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