Rafael Nadal and Novak Djokovic stepped up with straight-set, first-round victories on Tuesday as both former champions began their quests to add to their Australian Open ­legacies.

Djokovic, bidding for a seventh title at the tournament, held off Spain's Fernando Verdasco 6-1, 7-6 (7-4), 6-2.

Nadal started the chase for his first Melbourne Park title in eight years by dispatching German Florian Mayer 6-3, 6-4, 6-4.

Nadal, who is the last lefthander to claim the title, ran his record at the Slam to 46-10.

"I played (a) solid match, it was great to be back on the big stadium," Nadal said. "I'm happy the way I am playing. But it's never easy, the first round.

"It's always a little bit more nerves at the beginning. I'm happy the way that I played. I played good all the key points. That's very important for me."

Djokovic successfully dispelled a dangerous opponent in Verdasco, who forced the Serb to save five match points this month in Qatar and also took out Nadal in the first round a year ago.

French sixth-seed Gael Monfils beat Jiri Vesely 6-2, 6-3, 6-2 while Austrian eighth-seed Dominic Thiem got past German Jan-Lennard Struff 4-6, 6-4, 6-4, 6-3.

Croatian Ivo Karlovic fired 75 aces in a marathon that broke numerous records, as he triumphed over Horacio Zeballos 6-7 (6-8), 3-6, 7-5, 6-2, 22-20.

Belgian David Goffin, seeded 11th, struggled to contain Reilly Opelka, finally taming the 6-foot-11 American 6-4, 4-6, 6-2, 4-6, 6-4.

On the women's side, Serena Williams, aiming for an Open-era record 23rd major title, had a straight set win over Belinda Bencic. The 19-year-old applied pressure on Williams who made mistakes on key points — including a double-fault to give Bencic a break point, and another on her first match point — before recovering to win 6-4, 6-3.

After improving her record in the first round of majors to 65-1, Williams will play Lucie Safarova, who saved nine match points before beating Yanina Wickmayer 3-6, 7-6 (7), 6-1.

Defending champion Angelique Kerber and top-seeded Andy Murray play their second-round matches on Wednesday in much more pleasant temperatures at Melbourne Park. A cool change hit the city overnight, dropping temperatures from 100 Fahrenheit on Tuesday afternoon to about 68 when play began Wednesday.