Madrid - American eighth seed John Isner became the first significant casualty at the Madrid Open when he was pipped 7-6 (7/4), 7-6 (7/3) in the second round by fellow big-serving giant Marin Cilic on Wednesday.
Unseeded Croat Cilic, who stands at 1.98m to Isner's 2.06m, produced when it counted in the tie-breaks on the blue clay at the Magic Box arena, winning the first 7-4 and the second 7-3, to set up a meeting with either former US Open champion Juan Martin Del Potro or Mikhail Youzhny.
Neither player managed to break the other's serve as Cilic followed up his five-set victory over Isner at last year's Australian Open, their only previous meeting, with another narrow success.
Isner refused to blame the reverse on the blue clay, a controversial innovation at this year's edition of the Masters event that has prompted harsh criticism from players including world No 1 and defending champion Novak Djokovic and No 2 Rafael Nadal.
Djokovic slammed organisers and the ATP after his laboured second-round win on Tuesday, saying the Manolo Santana show-court was too slippery and accusing officials of ignoring players' concerns.
"I lost because I didn't do what I should have done out there and he was better than me," Isner told a news conference.
"I always felt that this tournament even with the red clay was the most slippery I have ever played on," added the 27-year-old.
"It's tough for a big guy like me but my opponent was also a big guy and like I said he was just better and deserved to win and I did not deserve to win.
"I just didn't play particularly well today which has nothing to do with the courts."
Spaniard Nadal, who is chasing a third straight clay title of the season, gets his campaign under way later on Wednesday with a second-round clash against former world No 3 Nikolay Davydenko of Russia.
Current No 3 Roger Federer then plays fast-rising Canadian Milos Raonic, who took a set off the Swiss maestro at the Indian Wells Masters in March.
Djokovic, who beat Nadal in last year's final, will meet another Swiss, unseeded Stanislas Wawrinka, in the third round on Thursday.