The Dutch were dominant throughout and tiny Slovakia rarely came close to repeating their shock elimination of holders Italy last week, although Robert Vittek scored a consolation penalty just before the whistle. [break]
Arjen Robben, making his first start, picked up a superb long ball from Wesley Sneijder and slammed in a lovely left-footed shot in the 18th minute. Sneijder doubled the score six minutes from the end at the match in Durban.
In the quarters, the Dutch will play the winners of the second round game between Brazil and Chile later on Monday.
Fans in Johannesburg will be watching impatiently to see if Brazil can finally show off some of their famous flair in another David and Goliath contest.
The Samba Boys will want to match the style that took Latin American rivals Argentina into the quarter-finals with a 3-1 defeat of a tough Mexican side on Sunday.

Chile start as real underdogs against the five-times champions -- they have lost seven matches in a row, conceding 26 goals in the last five years in matches between the two.
While Netherlands went through comfortably after maintaining their perfect record, England wallowed in shame after a humiliating 4-1 defeat on Sunday by Germany, which resulted in a torrent of British press abuse.
CAPELLO SHAKEN
Their shaken Italian manager Fabio Capello said he wanted to stay in the job, despite England´s worst defeat at a World Cup, but told reporters his future would be decided after two weeks reflection by the Football Association.
The humiliation of another European soccer power, France, claimed the head of the president of their federation on Monday when Jean-Pierre Escalettes resigned.
France, runners up in 2006, went out bottom of their group following a chaotic players´ revolt. French Sports Minister Roselyne Bachelot said last week Escalettes should resign.
Argentina´s defeat of Mexico set up a quarter-final clash with Germany.
The Germans´ quashing of the over-ambition that seems to accompany England to every international tournament unleashed a torrent of abuse in the British press both of the failing Premier League millionaires and Capello, considered the team´s savior until the miserable World Cup showing.
Newspapers were brutal, with words like awful, humiliating, calamity and catastrophe littering the headlines.
Commentators agreed that a refereeing error that disallowed a clear first half goal from Frank Lampard was no excuse.
"You let your country down," the mass circulation Sun said on its front page.
GERMAN YOUTH
The youthful Germans were simply too fast for England, who lacked vital pace in defense and were outplayed and out-thought.
The beaming post-match smile of veteran attacker Miroslav Klose, who came into the World Cup battered by criticism after a trickle of domestic goals, was a telling contrast to the miserable scowl of Wayne Rooney, who had been tipped to be one of the biggest names here.
The refereeing blunder over Lampard´s disallowed goal and a clear offside in Carlos Tevez´s first goal for Argentina revived heated debate over FIFA´s stubborn refusal to use the technology adopted by almost all international sports to help decide on vital close calls. Soccer´s governing body earlier this year ruled out the use of such a system in the foreseeable future.
South African immigration officials have stopped 613 "undesirable" people from entering around the World Cup, they said on Monday. They did not say how many were potential hooligans but have worked closely with foreign police to keep out known troublemakers.
Netherlands set Thailand 123-run target to win