exhibition match at the Bermuda Open, but Patrick Rafter admits clay is hardly his favourite surface.

However, the two-time defending US Open champion, returning to competitive singles action at the AT&T Challenge in Atlanta, would have expected to easily beat unseeded Martin Rodriguez in the first round.

But after a 45-minute rain delay left the first set deadlocked in a 5-5 tiebreaker, the top-seeded Rafter unraveled in a 7-6 (7-5), 7-6 (7-5) upset.

"Those were tough conditions out there,'' the fourth-ranked Australian said.

"But I'm really not playing well enough yet to know what to expect from my game.'' Rodriguez was a surprise winner, especially after losing a qualifying match 3-6, 7-6 (7-5), 6-0 to Uruguay's Marcelo Filippini on Sunday. Rodriguez made the field only because he was the highest-ranked player among the qualifying losers after Christian Ruud and Laurence Tieleman pulled out.

The surface "was heavy to start with, but I just couldn't play the style of game I wanted,'' Rafter said. "It's a pathetic situation for me because I feel very little confidence.'' Third seed Vince Spadea was beaten by Bermuda Open competitor Max Mirnyi, who continued his splendid form after putting Jim Courier out of the US Clay Court championships last week. Bermuda Open finalist Guillermo Canas, who made the final at Orlando on Sunday, defeated Australian sixth seed Scott Draper in the first round before succumbing to Spaniard Alberto Martin.