By John Pye

Caroline Wozniacki is entering new territory at the Australian Open as a defending champion for the first time at a major. For Roger Federer, though, it’s a well-worn experience.

A women’s final last year featuring two players aiming for their first Grand Slam title finished with Wozniacki holding off top-ranked Simona Halep for the title.

Federer beat Marin Cilic to win the Australian Open for the sixth time — claiming his 20th major crown — and successfully defend the title he won the previous year in a career comeback of sorts.

At 37, he’s still targeting records at his record-equalling 20th Australian Open: to be the first man to win seven Australian Opens, the first man to win at least seven singles titles at two Grand Slam tournaments (he has eight Wimbledon titles), and the first man to win five major titles after turning 30.

Of course, he’s got strong competition from Novak Djokovic, who has won the last two majors and is also aiming for a seventh Australian title. Then there’s a resurgent Rafael Nadal, the likes of Cilic and Sasha Zverev. But there’s unlikely to be another run to the final for Andy Murray, who wants to start the tournament where he has reached the final five times but is unsure how much longer he can play because of the pain in his surgically repaired right hip. He’s targeting retirement at Wimbledon.

Federer, the sport’s senior statesman, was asked Sunday how he retained such a high level of health despite being about five years older than Nadal, Djokovic and Murray — the other members of the socalled Big Four.

“Maybe also the way I play tennis, maybe it’s smoother than the other guys,” said Federer. “It just maybe looks that way. I work extremely hard in the matches as well — it just maybe doesn’t come across so much. I don’t know if that’s also something that maybe is part of the equation.”

He said he was shocked at Murray’s announcement, at 31, of his pending retirement. “It hits us top guys hard because we know Andy very well. We like him. He’s a good guy, Hall of Famer, legend,” Federer said. “It’s a tough one, but one down the road he can look back on and be incredibly proud of everything he has achieved.”

Federer, aiming for his 100th career title, will open against No 99-ranked Denis Istomin on Rod Laver Arena on Monday, likely after Murray has taken on No 22-seeded Roberto Bautista Agut on Melbourne Arena. Istomin had a shocking secondround win over Djokovic in 2017. “I know what Denis did to Novak. I watched basically the entire game a couple years ago,” Federer said. “Look, I’m playing good tennis. I’m confident that I think it needs a good performance by my opponent probably to beat me. That’s always a good thought.”

Wozniacki has the first of the night matches on Rod Laver against Alison Van Uytvanck after a day session on the main stadium that features Maria Sharapova, Nadal and No 2-ranked Angelique Kerber. “I think it’s a positive to be here as the defending champion. I’m just taking it as a nice, fun challenge,” the third-seeded Wozniacki said. “I can’t believe it’s already been a year. It doesn’t feel like it to me.” Wozniacki revealed at the seasonending WTA Championships that she’d been diagnosed with rheumatoid arthritis, so she spent much of the off-season resting and recuperating and getting ready for 2019. After her breakthrough here last year, she didn’t get beyond the fourth round at the other majors, but says she’s hitting the ball well.

French Open winner Halep and US Open champion Naomi Osaka collected their first major titles last year, and Kerber won at Wimbledon to capture her third in a sequence of eight different women’s winners in eight Slams. Serena Williams was unable to defend her title here last year because she was taking time out after having a baby, and finished the season with runner-up finishes at Wimbledon and the US Open. Now she’s back on the tour, seeded 16th, aiming for an eighth Australian title. The 23-time major winner is in the same section as her sister Venus Williams and Halep, who all start action on Day 2.