Ivo Karlovic crashed out to plucky American qualifier Tim Smyczek on the opening day of the Australian Open with a disappointing straight-sets defeat.

Smyczek only made the first-round draw as a lucky loser but got off to a bright start against Karlovic, taking a tight first set by a single break.

Karlovic used his huge serve to respond but with neither man making a mistake the second set went to a tie-break.

The breaker saw both men stay in fine form but the persistent style of Smycek finally forced a breakthough, winning 7-5 to claim the second set.

Again a single break of serve decided the third set as Karlovic tried in vain to keep the match alive.

Smyczek belied his world ranking of 125 to stay composed and claim the match in straight sets and book a second-round clash with David Ferrer, who eased through earlier today.