Rafael Nadal, Daniil Medvedev cruise into round 2 at Australian Open; Jo-Wilfried Tsonga retires with injury

Rafael Nadal had a 6-2, 6-3, 6-0 win over Hugo Dellien in his first competitive match back on Rod Laver Arena since losing the Australian Open final to Novak Djokovic last year.

The top-ranked Nadal is chasing his 20th major singles title, aiming to equal Roger Federer's men's record. He's also aiming to complete a collection by winning each of the four Grand Slam titles at least twice. He won the Australian title in 2009 and has lost four finals since then at Melbourne Park.

The 33-year-old Nadal dropped a service game once in each of the first two sets but was too dominant for No. 73-ranked Dellien, a Bolivian who was playing his first match at the season's first major and had only played five previous matches in the main draw of a major.

“It's a positive start," Nadal said. “What you want in the first round is to win, and straight sets is better."

In another night match, last year's U.S. Open runner-up, Daniil Medvedev, beat last year's Australian Open quarterfinalist Frances Tiafoe 6-3, 4-6, 6-4, 6-2 on Rod Laver Arena.

“It was a really tough match," the fourth-seeded Medvedev said. “Up and down from both of us.”

A back injury has forced 2008 Australian Open runner-up Jo-Wilfried Tsonga to retire from his first-round match against Alexei Popyrin after falling behind two sets to one.

The 34-year-old Frenchman won the first set in a tiebreaker before losing the next two sets 6-2, 6-1, calling for a trainer and then notifying the chair umpire that he could not continue.

“I have a back problem," Tsonga said. “It's annoying, annoying me when I play since I arrived from Doha, I've got some pain.

"So, yeah, it's difficult for me to deal with it for the moment. It's new. I will go home and see with my doctors what I have to do exactly and think about it."

Tsonga lost the final at Melbourne Park to Novak Djokovic 12 years ago.

The lights went out on Melbourne Arena in the second set of Nick Kyrgios' first-round match against Lorenzo Sonego.

As the players sat on courtside chairs, taking a breather during an enforced break, people in the crowd waved cell phones in the air to shine some light, giving the stadium a concert-like vibe.

Kyrgios said he likes to play at the arena, one of the three covered stadiums at Melbourne Park, because the crowds really get into it.

The interruption didn't last long, and soon Kyrgios took the second set in a tiebreaker for a 6-2, 7-6 (3) lead in the best-of-five match.

Alexander Zverev overcame a frustrating buildup to the decade's first major to win his first-round match against Marco Cecchinato 6-4, 7-6 (4), 6-3.

After the match, he told the crowd at Margaret Court Arena about his pledge, starting with the promise per match and then adding: “I know I'm not the favorite to win this event, but if I win this event, I'll donate every single cent to the bushfires.”

The singles champions earn more than 4 million Australian dollars, and have to win seven consecutive matches to clinch the title.

Zverev hasn’t won a major title — his best run so far is to the quarterfinals at the French Open in the last two years. But he is considered one of the rising stars of men’s tennis, has a career-high ranking of No. 3 and won the season-ending ATP Finals in 2018.

Zverev struggled with his serve at the ATP Cup earlier this month in losses to Alex de Minaur, Denis Shapovalov and Stefanos Tsitsipas. It worked better at Melbourne Park, where he served only four double-faults in his opening match.

On the scoreboard it looks like a routine three-setter, but it took two days and a lot of disruptions for Milos Raonic to advance to the second round at the Australian Open.

Raonic was leading by two sets and 5-2 when heavy rain suspended his opener against Lorenzo Giustino, a lucky loser from qualifying who got a spot in the main draw when Radu Albot withdrew an hour before the first round on Monday.

The 2016 Wimbledon finalist returned on Day 2 to complete a 6-2, 6-1, 6-3 win. There was no need to rush it through on the opening day, said Raonic, who has been troubled by a series of injures and was the lowest-ranked of the 32 seeds in Australia.“If I was serving, maybe I would have rushed it. But to receive and have to move, I don't think so,” he said. “And the rain came down pretty quickly. Once it started -- it wasn't like there was a moment of maybe we could have played one or two points in the moments where it was drizzling at the beginning.”

Raonic reached the quarterfinals here last year and the fourth round at Wimbledon, but missed the French Open and U.S. Open because of injuries.

“Since the end of the season, I took time to recover my back and take care of a few other things,” he said. “I was able to train for about six, seven weeks straight without any hindrances, no setbacks. I was thankful for that.

“To start off in that way, especially not having played a lot of matches, to play a pretty clean match and obviously to come back today and be efficient, all of those things are positive, something I can build off.”

In another match played across two days, No. 12-seeded Fabio Fognini rallied from two sets down to hold Reilly Opelka 3-6, 6-7 (3), 6-4, 6-3, 7-6 (5).