Nadal and Murray move on, Del Potro exits

By Julian Linden

MELBOURNE (Reuters) - U.S. Open champion Juan Martin Del Potro was knocked out of the Australian Open on Sunday, joining two other giants who came to a grief at tournament where it seems size no longer matters.

Rafa Nadal and Andy Murray also brought down a pair of enormous opponents to set up a tantalizing quarter-final between two of the biggest names in men's tennis.

Nadal defeated Ivo Karlovic, a 2.08m (6ft-10in) Croatian whose serves come down like thunderbolts, 6-4 4-6 6-4 6-4, while Murray beat the 2.06m (6ft-9in) American John Isner 7-6 6-3 6-2.

There are plenty of giant-killers in the women's draw too.

Justine Henin may be small in stature but what she lacks in size she makes up for in determination and her fairytale comeback is building momentum.

She beat fellow Belgian Yanina Wickmayer 7-6 1-6 6-3 to reach the last eight in just her second tournament back from retirement and will play Nadia Petrova, who upset Svetlana Kuznetsova two days after knocking out U.S. Open champion Kim Clijsters.

SHOOTOUT

Nadal's match against Karlovic was not one for the traditionalists. It was more like pistols at dawn than the genteel game once played at Victorian garden parties.

Karlovic rifled 28 aces past the Spaniard but the defending champion knows a thing or two about how to win.

The world number two remained patient, rolled the dice a few times and correctly gussed which way to go, then took his chances when they came and is safely through to the last eight.

"I thought I returned really well," Nadal said. "When I had the chance to touch the ball!"

Isner is an inch shorter than Karlovic but his serve is no less lethal. The American had thumped down 81 aces in his first three matches and added 14 more against Murray.

The Scotsman is one of the best returners in the game and he showed why, frustrating Isner with his ability to get the ball back in play.

Unlike Karlovic, Isner does not rely just on his serve and volley and was happy to go behind the baseline and rally with Murray, another strength of the world number four.

"I'm happy to have won the matches comfortably," said Murray, who is yet to drop a set at Melbourne Park this year and brimming with confidence.

"I know the match against Rafa is going to be difficult, but I think I can win. I just need to make sure I play my best."

There were concerns about Del Potro's fitness even before the first grand slam of the year began. He pulled out a warm-up tournament but played the Open with his ankles and wrists heavily bandaged.

He survived a five-set marathon with James Blake in the second round and his two other matches both went four sets but ran out of gas against Cilic, an underrated player ranked 14th in the world who will meet either Andy Roddick or Fernando Gonzalez.

"I will go home and I will see the doctors there," Del Potro said. "I need a little rest to recover and be in good shape for my next tournament."

SLAUGHTERED

Henin's next opponent is Petrova who slaughtered Clijsters on Friday then added the French Open champion to her list of victims on Sunday, winning 6-3 3-6 6-1.

Kuznetsova looked tired after her previous match had finished just before 2 a.m. on Saturday but did not use that as an excuse for her poor performance.

"I was not good today. I think I deserve to lose," she said.

Russia are already assured of at least one more female quarter-finalist with world number two Dinara Safina and the unseeded Maria Kirilenko drawn together.

The winner of that match will play China's Zheng Jie, who defeated Ukraine's Alona Bondarenko 7-6 6-4.

(Editing by John O'Brien)