MELBOURNE, Australia — After wasting a set point in the second tiebreaker with an ill-conceived drop shot, Jannik Sinner regained focus quickly Monday and began his Australian Open title defense with a 7-6 (2), 7-6 (5), 6-1 win over Nicolas Jarry.

After all the pre-tournament attention on the 2024 doping cases of Sinner and long-time women's No 1 Iga Swiatek, both started the year's first Grand Slam tournament about the same time on nearby courts on Day 2.

Top-ranked Sinner had to grind for two long, tiebreak sets against No 35-ranked Jarry, a 29-year-old from Chile, before hitting his stride in the third with two service breaks on Rod Laver Arena.

"It was a very close one because the first two sets, they can go both ways," Sinner said after extending his winning streak to 16 matches dating back to October, including 14 consecutive straight-sets victories. "In the third set when I broke it the first time, that gave me a little bit of room to breathe.

"I'm happy how I handled the very tough situation."

Sinner has got a good record at Melbourne Park in that department. He rallied from two sets down in last year's final to beat Daniil Medvedev for his first Grand Slam title, coming off a semifinal upset of 10-time champion Novak Djokovic.

With Australian player Nick Kyrgios particularly scathing about Sinner's doping case, the Italian said he was curious how fans at Rod Laver Arena might react.

As it was, Sinner was cheered warmly as he took the court, and throughout his win over Jarry in the afternoon sunshine.

"You never know what's happening. I was happy about the crowd. It was a very nice crowd. There were some (support) for my opponent and some for me," he told reporters.

"It was a nice atmosphere."

While Sinner was deep into his match against Jarry, Swiatek, a five-time major winner from Poland, fended off top-ranked doubles player Katerina Siniakova 6-3, 6-4 on John Cain Arena.

The 23-year-old said a blast of Australian rockers AC/DC had helped get her in the mood for her solid but unconvincing win over Czech Siniakova.

"Before matches, appropriate music makes me feel more energized and sometimes I hum it during the match," said the world No 2, who served a short doping ban last year.

In her match against the 50thranked Siniakova, Swiatek struggled to find the deliberate rhythm that has helped her win five Grand Slam titles as her opponent, a doubles specialist, put up some stiff resistance.

"For sure it wasn't an easy first round so I'm happy I got through," said Swiatek, who will next play Rebecca Sramkova of Slovakia.

"I felt like she was playing really well and I knew I needed to be more proactive when I wanted to and at the end in the second set I did that."