Isner blasts away top seeded Robredo in Auckland

By Greg Stutchbury

AUCKLAND (Reuters) - Big-serving American John Isner advanced to the Auckland Open semi-finals for the first time with a three-set victory over top seed Tommy Robredo on Thursday.

The 24-year-old Isner, who was knocked out at the quarter-final stage last year, overpowered the 16th ranked Robredo with 20 aces to run out a 7-6 3-6 6-4 winner.

A noticeably frustrated Robredo said that while he had broken Isner's booming serve three times, he still had trouble with a ball that was clocked moving at more than 220 kilometers per hour (137mph).

"I feel good. I'm not going to change much from the way I played or am feeling," Robredo said.

"I played great from the baseline, was returning great and only had a couple of mistakes with my serve. The rest is positive for me, even though I lost, but if you play a guy like John, it can happen."

Robredo's demise ensured that none of the top four seeds would be in the semi-finals on Friday.

Isner will now meet Spain's Albert Montanes in the semi-finals after the eighth seed beat Swiss qualifier Michael Lammer 6-3 6-3.

Isner said he doubted if the ease of the Spaniard's path would have any bearing on their match.

"He has a deceptively strong serve," Isner, who beat Montanes in Auckland last year, added. "He's also very fast and has some great groundstrokes... so it will be tough."

France's Arnaud Clement continued a strong run with a 6-2 7-5 victory over sixth-seeded Austrian Juergen Melzer and will meet 2008 champion Philipp Kohlschreiber, who beat France's Marc Gicquel 6-3 6-1 in the late match, in the final four.

(Editing by John O'Brien)