Second seed John Isner is the latest big name casualty of the ASB Classic after falling to his American compatriot Steve Johnson in today's quarterfinals.

Isner won his place in the final eight after triumphing over Malek Jaziri in third-set tiebreak in yesterday's second round, but he could not repeat the heroics today. Instead it was Johnson who found the edge after the third set was forced into a tiebreak, going on to claim a 6-3 5-7 7-6 (3) win.

Johnson started strongly in the match, doing a solid job of exploiting his 2.08m opponent's lack of mobility around the court.

But Isner found a better rhythm in the second set, building strong momentum from his impressive serving game.


Trailing 6-5 in the second set, an errant drop shot from Johnson ensured Isner converted a crucial break point and send the match to a third set - much to the frustration of his opponent. Johnson smashed his raquet into the ground as he walked to his seat and could be seen remonstrating with himself during the break for the lapse.

The third set proved to be another arm wrestle, with neither player able to find the break they needed.

Johnson join Portugese player Joao Sousa in the semi-finals, who defeated Dutchman Robin Haase in straight sets to advance this afternoon.

After taking out the opening set 6-3, Sousa dominated his opponent in the second, forcing two early breaks and eventually prevailing 6-2.

Yesterday, Haase ousted four-time champion and third seed David Ferrer, but he couldnot recapture that form against Sousa, who sits 14 spots higher on ATP rankings.

Sousa will now face the winner of Jiri Vesely v Marcos Baghdatis.