MELBOURNE, Australia — There was no easing into a title defence for Novak Djokovic, starting his Australian Open against the man who upset Rafael Nadal here last year in the first round.

Djokovic lifted when he most needed to Tuesday night, holding off Fernando Verdasco in a 71-minute, momentum-swinging second set before winning 6-1, 7-6 (4), 6-2. There were glares, stares and frustrated outbursts from players who met in a tense semifinal earlier this month in Doha, where Djokovic saved five match points en route to victory.

"I'm very pleased with the first round, considering I had one of the toughest first-round draws, definitely considering his form, " said Djokovic, who is aiming to be the first man to win seven Australian titles. "Just overall I'm feeling good about my performance."

Another six-time champion had a tough first round, with Serena Williams needing to produce some of her best tennis to get far enough ahead against Belinda Bencic that a late lapse wasn't a real worry.

And after starting her quest for a record 23rd Grand Slam title with a 6-4, 6-3 first-round win, Williams walked into her news conference wearing a black shirt with the word "Equality" printed across the front.

It was still before midnight Monday in the United States, where the holiday in honour of civil rights leader Martin Luther King Jr. was nearly ending.

"With today being Martin Luther King Day, it's important to spread the message of equality," Williams said. "Something he talked about a lot and he tried to spread a lot, is equality and rights for everyone."

Asked if she was concerned about the future of equality in the U.S., Williams declined to get into specifics but said the issue is "a concern for just everyone in general."

Williams became engaged to Reddit co-founder Alexis Ohanian during the holiday break, and he was in the crowd watching her play at Rod Laver Arena. She has been asked repeatedly about her wedding plans since arriving in Australia. She gave a clearer time frame for discussion on that.

"February I'll start looking at the bigger picture of my life," she said. "But right now I'm just so focused that this is kind of all I can think about."

Williams played almost flawless tennis to take a 5-0 lead in the second. Then came the rustiness that tends to follow a lengthy layoff.

But after three double faults — including one on match point — and "some errors on key points," Williams held on to improve her record in the first round of majors to 65-1. She'll next play Lucie Safarova, who saved nine match points before beating Yanina Wickmayer 3-6, 7-6 (7), 6-1.

Nadal, also on the comeback from a couple of months on the sidelines following the U.S. Open with an injured left wrist, had a 6-3, 6-4, 6-4 win over Florian Mayer to go one better than he did last year in Australia.

"I'm happy to do an interview with you — last year, I didn't have the chance!" Nadal said in his on-court interview.

In a 5-hour, 15-minute encounter on Court 19, 37-year-old Ivo Karlovic held off Horacio Zeballos of Argentina 6-7 (6), 3-6, 7-5, 6-2, 22-20 in a match that set a record for most number of games (84) at the Australian Open in the tiebreak era. Karlovic also finished with a tournament-record 75 aces.

On a day when the temperature reached almost 38 Celsius (100 Fahrenheit), third-seeded Milos Raonic, who reached the semifinals in Australia last year and the final at Wimbledon, beat Dustin Brown 6-3, 6-4, 6-2 and No. 11 David Goffin beat 19-year-old qualifier Reilly Opelka 6-4, 4-6, 6-4, 4-6, 6-4.

Also advancing were No. 8 Dominc Thiem, No. 13 Roberto Bautista Agut, No. 15 Grigor Dimitrov, No. 18 Richard Gasquet, No. 24 Alexander Zverev, No. 25 Gilles Simon, and No. 32 Philipp Kohlschreiber.

The women who won the titles in warmup tournaments in Brisbane and Sydney advanced in straight sets.

U.S. Open finalist Karolina Pliskova, the Brisbane winner, had a 6-2, 6-0 victory over Sara Sorribes Tormo. Sydney champion Johanna Konta, a surprise semifinalist in her debut at the Australian Open last year, had a 7-5, 6-2 win over Kirsten Flipkens.

No. 6 Dominika Cibulkova, former No 1-ranked Caroline Wozniacki, No. 14 Elena Vesnina, No. 21 Caroline Garcia, No 28 Alize Cornet, No. 30 Ekaterina Makarova also advanced.

Heather Watson extended the 2011 U.S. Open winner Sam Stosur's drought at her home Grand Slam, winning 6-3, 3-6, 6-0.