Fourth seed Guillermo Canas of Argentina maintained his perfect record against Thomas Johansson by beating the Swede 6-3 7-6 in the Las Vegas Open first round.

The 30-year-old player 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.

In an earlier match, eighth-seeded Nicolas Kiefer fired down eight aces to beat fellow German Benjamin Becker 6-4 6-3.

Second-seeded Lleyton Hewitt, the defending champion, was scheduled to play wildcard Marat Safin of Russia in one of the day's late matches.

Australian 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.

Hewitt has won an ATP Tour event in each of his 10 years as a professional.

Reuters