The Spaniard, who will be seeded fourth at Melbourne Park next week in the absence of compatriot Rafa Nadal, needed just 54 minutes to beat his Slovak opponent and set up a semi-final against France's Gael Monfils, who later beat Tommy Haas 3-6 7-5 6-3.
The fifth seed in the men's draw for the year's first Grand Slam, Tomas Berdych, had a less enjoyable day when he was humbled 6-3 6-2 by resurgent former world number one Lleyton Hewitt at the Kooyong Classic.
Australian Hewitt, now 31 and ranked 82nd in the world, beat world number 15 Milos Raonic in his first round robin match on Wednesday and his 88-minute victory over Czech Berdych puts him into the final of the exhibition event.
There he will meet either Argentina's world number seven Juan Martin Del Potro or Cypriot Marcos Baghdatis, who face off at Kooyong on Friday.
"I'm just thrilled to be able to perform like this against quality players and on back-to-back days," Hewitt said.
"I've had five tough sets in two days and that will hold me in good stead for next week."
The men's event at the Sydney International warm-up reached the quarter-final stage with just one seed still standing after upsets and injury withdrawals ravaged the draw.
Frenchman Julien Benneteau, well rested after his second round tie on Wednesday went just four points before Radek Stepanek retired hurt, cruised past American qualifier Ryan Harrison 6-4 6-2.
South Africa's Kevin Anderson joined him in the semi-finals with an equally straightforward 6-4 6-3 win over Denis Istomin of Uzbekistan.
Australian young gun Bernard Tomic defeated defending champion Jarkko Nieminen 6-7 6-4 6-2 in his quarter-final later and will go on to play third seed Andreas Seppi in the last four after the Italian saw off Marcel Granollers 6-4 7-5.
Men's top seed John Isner, who lost to Harrison on Wednesday, pulled out of the Australian Open because of a knee injury on Thursday leaving Sam Querrey as the only American men's seed at Melbourne Park this year.
Querrey overcame Canada's Jesse Levine 6-4 7-6 in Auckland and will face Philipp Kohlschreiber in the semi-finals after the German beat Xavier Malisse 7-6 6-4.
ATP Sydney results
3-Andreas Seppi (Italy) beat 8-Marcel Granollers (Spain) 6-4 7-5
Bernard Tomic (Australia) beat Jarkko Nieminen (Finland) 6-7(6) 6-4 6-2
Julien Benneteau (France) beat Ryan Harrison (US) 6-4 6-2
Kevin Anderson (South Africa) beat Denis Istomin (Uzbekistan) 6-4 6-3
ATP Auckland results
1-David Ferrer (Spain) beat Lukas Lacko (Slovakia) 6-2 6-1
4-Sam Querrey (US) beat Jesse Levine (Canada) 6-4 7-6(5)
2-Philipp Kohlschreiber (Germany) beat Xavier Malisse (Belgium) 7-6(6) 6-4
Gael Monfils (France) beat 3-Tommy Haas (Germany) 3-6 7-5 6-3