Rafael Nadal, the second seed, set up a quarter-final tie with Andy Murray with after a hard-earned win over the Croatian Ivo Karlovic in the fourth round of the Australian Open. The Spaniard faced a tough challenge from the big-serving Karlovic, but eventually overcame his opponent, all 6ft10in of him, 6-4, 4-6, 6-4, 6-4.

Karlovic, with his massive serve, has proved a tricky opponent for even the best players on the tour and predictably rained down 27 aces on Nadal. However Nadal was always the classier of the pair, and eventually negated Karlovic's biggest weapon to confirm his match against Murray, who earlier saw off another big server, John Isner.

While Karlovic's serve was daunting at times, he was characteristically unable to make much impact when the tables were turned and Nadal was patient before taking the first set. The Croatian, ranked 39 in the world, upped his game in the second, however, breaking at the first opportunity before going on to seal the set easily.

Yet Nadal is nothing of not persistent and forced a break early in the third set, which was all it took to restore his advantage. Normal service resumed, Nadal was unlikely to let Karlovic back into the match and saw out the fourth set with ease to seal the match.

"I know how tough Ivo is," said Nadal. "If he serves well you can do nothing. I stayed focused and relaxed and tried my best."

The world No2 hopes the win will boost his confidence ahead of the showdown with Murray, who is yet to drop a set in the tournament so far. However Nadal remains acutely aware of the difficulties the British No1 will present him.

"I hope so, I don't know," Nadal said. "Being in the quarter-final is very good for me, it's given me a lot of confidence but I know I have got a really difficult match against Andy. I just wanted to enjoy it today."

"Andy is one of the most talented players on the tour. He can play aggressively, defensively.

"I will just try to play my game with the forehand and put him a bit behind the baseline, maybe one metre, two metres. If not, maybe I'll have a good flight home!"