|World number one Nadal was made to sweat against young Australian challenger Tomic [AFP]
Rafael Nadal outmuscled 18-year-old local hope Bernard Tomic in an absorbing 6-2 7-5 6-3 win to reach the last 16 of the Australian Open.
The world number one, bidding to become only the third man, and the first since 1969, to hold all four Grand Slam titles at once, was given a workout by the teenager under the floodlights on a packed Rod Laver Arena.
"I have to play better if I want to get to the quarter-finals," Nadal said in a courtside interview.
"I didn't have enough from the baseline to destroy him."
As the crowd laughed at his choice of words, a red-faced Nadal grabbed the microphone and added: "I'm sorry. I didn't have another English word."
Nadal, Melbourne champion in 2009, bombed through the first set, but Tomic came out swinging in the second, bursting into a 4-0 lead as the Spaniard suddenly appeared powerless against the youngster's onslaught.
However, a sweat-drenched Nadal came roaring back and finally took the second set 7-5 with a fierce serve down the middle.
A break at the start of the third set effectively ended Tomic's resistance and Nadal closed out proceedings after two and a half hours with a drilled backhand crosscourt that his opponent struck wearily into the tramlines.
Nadal, who next faces Croatia's Marin Cilic, can join Don Budge (1938) and Rod Laver (1962 and 1969) as the only men to hold all four major titles simultaneously if he wins his second Australian Open.
Earlier on Saturday Petra Kvitova shattered Australia's hopes of a first women's champion in their home event since 1978 by knocking out fifth seed Samantha Stosur 7-6 6-3 to advance to the fourth round.
The ice-cool 20-year-old Czech, who warmed up for the year's first Grand Slam by winning the Brisbane title, silenced the crowd at Rod Laver Arena by guiding a forehand volley down the line to seal victory in 95 minutes.
"I didn't have enough from the baseline to destroy him...I'm sorry. I didn't have another English word"
Rafael Nadal, world number one
Kim Clijsters also continued to glide through the women's draw even if the Belgian admitted she was not at her best in her 7-6 6-3 victory over Alize Cornet, which spoiled the Frenchwoman's birthday.
"You never play a whole tournament playing your best tennis and you have to also work for it," said the three-times US Open champion.
"I think that's what I had to do today."
Robin Soderling and Andy Murray served up reminders that there are more than two contenders for the men's title with dominant victories.
Murray was clinical in his 6-1 6-1 6-2 dismantling of Spain's Guillermo Garcia-Lopez.
"It was good," the Scot, who lost to world number two Roger Federer in the final here last year, said after the 82-minute contest.
"Obviously, it was a quick match. Served well. Hit the ball clean from the back. That was it."
Soderling's 6-3 6-1 6-4 trouncing of Czech qualifier Jan Hernych took longer but was equally comprehensive.
Both he and Murray have yet to drop a set this week and the Swede thought Nadal and Federer were not necessarily shoe-ins for the final.
"I think there's many guys who can actually compete against them and have a chance to win the tournaments like this when they're playing well," he said.
Like Soderling and Murray, Vera Zvonareva is still seeking her first Grand Slam title and she pulled off a 6-3 7-6 win over Lucie Safarova.
Two men's seeds had less successful days, however, with 10th-ranked Mikhail Youzhny crashing out 6-4 7-5 4-6 6-4 to Canadian qualifier Milos Raonic and 2008 runner-up Jo-Wilfried Tsonga losing 3-6 6-3 3-6 6-1 6-1 to Alexandr Dolgopolov.
There were fireworks on the Margaret Court Arena where last year's semi-finalist Marin Cilic beat marathon man John Isner 4-6 6-2 6-7 7-6 9-7 in a slug-fest that featured 58 aces to set up a meeting with Nadal or Tomic in the next round.
The Croatian mercifully sealed the victory after four hours, 33 minutes – some seven hours short of Isner's record match against Nicolas Mahut last year at Wimbledon – and the players embraced at the net.