Rio de Janeiro: World No 11 John Isner crashed out in the first round of the Rio Open, losing in three sets to Guido Pello yesterday.

The big-serving American had staved off two match points in the second set, but went on to miss two of his own in a 7-6 (7/5) 5-7 7-6 (8/6) win for the Argentine.

Pello, unseeded in the tournament, had to face 31 aces from Isner, but did enough in the final-set tie-breaker to earn a second career win against top-20 opposition.