Spain's Rafael Nadal reeled off another straight-sets victory to reach the Australian Open's last 16 on Friday, but he insisted everything was not as easy as it appeared.
The world number two, bidding for his 11th grand slam title in Melbourne, wore down Slovakian qualifier Lukas Lacko after a fiercely contested opening to claim a 6-2, 6-4, 6-2 victory.
Nadal has yet to drop a set in his three wins at the year's opening major tournament and will face either American John Isner or compatriot Feliciano Lopez in the round of 16 on Sunday.
The Spaniard has only failed once to reach the fourth round in eight visits to Melbourne, but he denied it was all coming too easily.
"I did well. I played three matches at very good level. Today was one of the best, solid, without mistakes, comfortable with the serve and good returns," Nadal said.
"Nothing is easy. Everything is difficult. Every match you have your problems. First set was 6-2, but I had to fight for it. It was a tough one."
"But I played solid all the match, so that's why I won."
Nadal wore down the 119th-ranked Lacko after being forced to work hard at the start of the match. The opening point was a 28-shot rally and the first two games occupied 14 minutes with the Spaniard losing his opening service game.
But the second seed went on to break Lacko's serve six times to complete victory in 1hr 55min on Rod Laver Arena.
Nadal hit 12 forehands among his 27 winners and forced Lacko into 32 forced errors with his high-intensity game from the back of the court.
"I am playing well. If you are playing well, things can be a little bit less difficult," he said.
The Spaniard claimed the Australian Open title in 2009 but was forced to retire hurt against Andy Murray in 2010, and was hampered by a left adductor injury in his quarter-final defeat to David Ferrer last year.
Nadal is currently joint sixth with Bill Tilden on the list of all-time grand slam men's singles champions behind Roger Federer (16).
Lacko, 24, reached the third round of a grand slam for the first time after defeating Croatia's 28th seed Ivan Ljubicic and American Donald Young.
He was bidding to become the first Slovakian men's player to reach the round of 16 at a grand slam since Dominik Hrbaty at the 2006 Australian Open.