Wozniacki, who held the year-end No. 1 ranking in 2010 and 2011 but is yet to win a major title, had high-profile support from McIlroy in the crowd and there was a buzz around Pat Rafter Arena amid rumours the pair had become engaged in the off-season.
The 22-year-old Danish player was photographed with a new ring on her left hand as she arrived in Australia last week, sparking speculation of pending nuptials. She explained Monday that the ring was a gift.
"It was a Christmas present and it fit on this finger and I put it on, and all of a sudden I hear that I'm engaged. But I'm not," she said. "So, yeah, it's already twice we've had to shut down engagement rumours. Don't worry, we will let you know if that time happens!"
On the court, Wozniacki raced to a 4-1 lead before finishing off the first set within a half hour. She started to struggle with her serve as she lost the second set and then had difficulty in the third countering powerful groundstrokes from the left-handed Pervak in the first upset result of the tournament.
No. 9-ranked Samantha Stosur was also upset in a night match, losing 7-6 (4), 7-5 to No. 41 Sofia Arvidsson of Sweden to continue her run of poor form in her native Australia since winning the 2011 U.S. Open. Stosur lost her second match at the Brisbane tournament last year, then had back-to-back first-round losses at the Sydney International and the Australian Open.
With eight of the top 10 women in the draw, the Brisbane tournament was expected to provide a good chance to fine-tune for the Australian Open starting Jan. 14. Now Wozniacki and Stosur will head to Sydney hoping for some decent match practice.
"I fought until the end. Maybe didn't play my best tennis today, but it's tough to expect that from yourself in your first match back," Wozniacki said. "Now I just have to play some practice matches with some of the other girls here and then go to Sydney and hopefully get a couple more there."
In other first-round matches, fourth-seeded Angelique Kerber of Germany opened with a 6-2, 4-6, 6-2 win over Anna Tatishvili of Georgia, French Open finalist Sara Errani beat Russia's Olga Puchkova 6-1, 6-3 and American Sloane Stephens beat Slovakia's Dominika Cibulkova 6-2, 6-3.
Alize Cornet of France advanced to a second-round match against third-seeded Serena Williams with an opening 2-6, 6-3, 6-1 over Australian qualifier Bojana Bobusic, and Germany's Sabine Lisicki opened with a 6-2, 6-4 win over Lucie Safarova of Czech Republic to set up a second-round match against top-ranked Victoria Azarenka.
The 103-ranked Pervak, who lost in the first round at 14 tournaments last year, including Brisbane, will play Urzula Radwanska of Poland on Tuesday. Pervak started to hit the lines in the second set against Wozniacki, showing match sharpness honed by playing in the qualifying tournament.
She was two points from victory, serving for the match at 5-3 and 30-15, but made a series of unforced errors to get broken and let the 10th-ranked Wozniacki get back into it.
Wozniacki held serve at love in the 12th game to force a tiebreaker but Pervak dominated from there, winning the first five points and securing the win with the first of her five match points when her rival missed with a timid forehand service return.
Stosur made 48 unforced errors and never settled into her rhythm after only two weeks of practice due to minor ankle surgery last month.
"Part of it can be put down to being a bit rusty and it's the first match of the year," she said. "I think a big part of it is that I haven't done enough."
In the men's draw, fifth-seeded Kei Nishikori of Japan beat Australia's Marinko Matosevic 7-5, 6-2; sixth-seeded Florian Mayer of Germany beat Santiago Giraldo of Colombia 6-4, 6-4; Jarkko Nieminen of Finland had a 6-3, 2-6, 6-1 win over Julien Benneteau of France; and Marcos Baghdatis, the 2006 Australian Open finalist, defeated Australian wildcard entry Ben Mitchell 6-4, 6-4.