After losing her world no.1 ranking and a 2016 season that she admitted did not live up to her standards, Serena Williams was back in action at a tournament that has been good to her in the past.

After minimal play since the US Open, Williams heated up quickly and overcame some rust to defeat Belinda Bencic 6-4, 6-3. It was a tricky opening round match for the world no. 2 as Bencic was ranked in the top 10 less than a year ago before injuries took her away from the court.

The two players went toe-to-toe early before Williams began to attack the second serve of the Swiss. The tactic forced Bencic to strike bigger second serves and created some errors. Meanwhile, Williams heated up offensively and rolled to a 5-0 lead in the second set. But Bencic exhibited fight and gained confidence, winning three straight games. It was not enough, however, as the 22-time major champion summoned enough to close out the set and match on her serve.

Serena acknowledged her early test afterward, “She's such a great player. She was just recently in the top 10 so she's been playing great,” she said. “It was one of the toughest first-round matches I've played so I knew I had to come out strong.”

Elsewhere, another ex-champion who missed some time in 2016, returned to action in Melbourne as well, as Rafael Nadal defeated Florian Mayer 6-3, 6-4, 6-4.

It was a workmanlike effort by the Spaniard who controlled business from the outset. The outcome was never in doubt as the left-hander moved Mayer around the court throughout the match.

Nadal faced no break points and capitalized on three of his 12 opportunities which were enough to control the match.

Asked about his health, Nadal responded. “The body is good and that’s the key. If the body is not good, everything is more difficult. After Roland Garros, everything was more difficult [last year], but that’s in the past.”

3rd-seeded Milos Raonic rolled in his first-round match, disposing of Dustin Brown 6-3, 6-4, 6-2. The Canadian is looking to go one match further than his semifinal result in 2016.

Raonic fired 17 aces, struck 46 winners and won 82 percent of his first serves as his power game was firing on all cylinders.