Danai, who had four successive early exits dating back to a grass court event in Nottingham last month, toppled the 161st-ranked Cakl 6-2 6-2. He had his revenge on the Czech, who he lost to in Binghamton in the US last year.

Danai benefited by below par serves from his rival and strode to a 5-1 lead in the first set, and after being level at 2-2 in the second, won the next four games in a row to close out the match.

A reward for his win is a match-up against top seed and world No 6 James Blake of the US. Blake, as well as all the seeded players including Thai No 1 Paradorn Srichaphan, the eight seed, received first round byes.

Paradorn will play either Wayne Arthurs of Australia or Harel Levy of Israel in the second round. But the Thai lost his first round doubles match when he teamed up with Gilles Muller of Luxembourg. They fell to Australian Stephen Huss and American Tripp Phillips in straight sets, 6-2 6-4.

Elsewhere, American teenager Sam Querrey fought back after losing a tie-breaker to post a 6-4 6-7 (4-7) 6-4 first round win over Serb Janko Tipsarevic. The 18-year-old is billed as the next big hope for the American game, but struggled at Roland Garros and Wimbledon.

With all 16 seeds given byes as the summer-long US Open Series begins in the mid-western city, Querrey drew attention after winning two lower-level Challenger titles in the past month.

Blake, the only American now ranked in the top 10, and No 11 Andy Roddick head the seedings. Chile's Fernando Gonzalez is the third seed and defending champion Robby Ginepri of the US is fourth.

Querrey, who is ranked 200th in the world, won his first set against Tipsarevic, ranked No 126, and held a 4-2 lead in the tie-breaker before his nerve failed.

But the teenager showed his determination thanks to a break in the opening game of the third set.

"After I was up in the breaker and let it slip, I told myself to stay positive," said the wild card entry, now 3-5 in ATP matches in his debut season.

"I told myself to get up a break in the third, and I was able to do just that.

"I'm getting wild cards and I hope to make the most of them. I'm hoping to win a match or two. I'm doing what I can to help American tennis."

The tournament features unseeded Australian Mark Philippoussis, who won his first title in nearly three years at Newport, Rhode Island, on Sunday over Justin Gimelstob.

Two-time former Grand Slam finalist Philippoussis, who cut his ranking almost in half to 125th with his victory, opens against German Benjamin Becker in the first round.

American Jeff Morrison beat Mexico's Santiago Gonzalez 6-2 6-2 to join Querrey in the second round.

The Nation, Agencies

Indianapolis