Nadal and Federer
The two champions are on course for a semifinal meeting at the Australian Open. Reuters

World number two Rafael Nadal and arch rival Roger Federer are on course to meet in the semifinals of the Australian Open, after both put in a strong showing to progress to the fourth round of the tournament.

Nadal showed glimpses of returning to his dominating best against Slovak qualifier Lukas Lacko, progressing with a 6-2 6-4 6-2 win in an hour and 55 minutes. He will now face the 18th seed Feliciano Lopez.

In addition to some much improved movement, ball striking and defence, Nadal's delivery, with a first-serve percentage of 81%, made a strong case for his comeback.

Afterwards, the Spaniard revealed his body was coping well, after an injury ravaged final month last season.

"The body is fine, I'm very happy to be in the fourth round," said the 25-year-old.

"It was a really complete, solid match and I'm very happy about my game. Being in round four without losing a set is fantastic."

Elsewhere, world number three Roger Federer was just as impressive against Ivo Karlovic, sealing his place in the fourth round with a tightly-contested 7-6 (8-6) 7-5 6-3 victory. He will now face Bernard Tomic.

It took two hours and 17 minutes for the 16-time Grand Slam champion to defeat the 57th-ranked Karlovic.

In an enticing first set tie-breaker, Federer made a mistake to give his opponent a 6-5 lead. However, he got back the point with an expertly taken lob, before claiming the next two and the first set.

Afterwards, he admitted anticipating a tough encounter.

"I knew it would be tough," said the third seed. "I've played him 10 times on tour and knew it could come down to a few points here and there.

"I needed a bit of luck too, especially in the tie-break. I definitely got fortunate but I got better as (the) match went on."