MELBOURNE, Australia -- Rafael Nadal wasted no time in reaching the third round, dropping only one service game -- while serving for the match -- and making just 10 unforced errors in a 6-3, 6-4, 7-6 (4) win over Leonardo Mayer on Wednesday.
Nadal, who won the French and US Opens last year but had his preparation for Australia delayed because of an injured right knee, called it "an important victory."
"I mean, he's a tough opponent. Leonardo is a player with big potential," said Nadal, the 2017 runner-up. "After a while without being on the competition ... second victory in a row, that's very important."
Nadal, who lost in the final here last year to Roger Federer, served for the match but was broken in the 10th game, with Mayer hitting a cross-court winner that clipped the line.
In the tiebreaker, Nadal won on his first match point with a service winner.
Local hope Nick Kyrgios, who upset Nadal in the fourth round at Wimbledon in 2014 as a 19-year-old, overcame distractions from a faulty speaker system at Hisense Arena and a lot of noise to beat Viktor Troicki 7-5, 6-4, 7-6 (2).
The 17th-seeded Kyrgios complained numerous times to chair umpire James Keothavong about noise coming from his microphone during points. Eventually, the umpire turned the microphone off and just shouted the score after each point.
Keothavong's night was about to get worse. With Kyrgios serving in the tiebreaker, Troicki hit an errant backhand return that slammed directly into the chair umpire's head. The Serbian player walked smiling to the umpire's chair to apologize, while Keothavong joked, "It's not my day, is it?''
Troicki fended off one match point in the ninth game of the third set and then broke in the next game to force the tiebreaker, but he couldn't challenge Kyrgios in the decider.
Kyrgios has advanced beyond the third round only once at his home Slam, when he reached the quarterfinals in 2015.
There was more drama earlier in the day on Margaret Court Arena, where Jo-Wilfried Tsonga came from 5-2 down in the fifth set to beat Denis Shapovalov 3-6, 6-3, 1-6, 7-6 (4), 7-5 in a second-round match.
Tsonga rallied to win in a 3-hour, 37-minute match that contained one of his nonchalant between-the-legs shots on an important point.
"It was a great get," Shapovalov said. "It was an unbelievable shot, don't get me wrong. I don't think it threw me off."
Tsonga broke the Canadian's serve for the second consecutive time to level the match at 5-5, including a full stretch sideways on break point on an attempted passing shot by Shapovalov.
Tsonga finally clinched it on his first match point, ending the 3-hour, 37-minute match.
"The most important thing for me was to fight, give my best on court until the last point," Tsonga said. "That's what I did today. I think he deserved to win also ... but I was also courageous, and I did my job at the end."
In what could be one of the most entertaining matches, Tsonga will play Kyrgios in the third round.
"He's one of my idols," said Kyrgios, who reached the 2014 Wimbledon quarterfinals at age 19 and ranked 144th. "I'm looking forward to going out there and battling it out with him."
Third-seeded Grigor Dimitrov scraped into the third round of the Australian Open -- just -- with a tough five-set win over 186th-ranked qualifier Mackenzie McDonald, a former NCAA champion from Los Angeles.
Dimitrov beat the 22-year-old McDonald 4-6, 6-2, 6-4, 0-6, 8-6 in a late-night match at Rod Laver Arena that went nearly three and a half hours.
McDonald double-faulted to set up match point, then netted a forehand to give Dimitrov the win.
"It's a tough day, obviously," Dimitrov said. "He played an unbelievable game. There's not much I can say -- experience in the end really helped me."
McDonald won the NCAA singles and doubles title for UCLA in 2016. He had never won an ATP or Grand Slam singles match in four attempts until his victory in the first round over a fellow qualifier on Monday.
Among the seeded men advancing were No. 6 Marin Cilic, who beat Joao Sousa 6-1, 7-5, 6-2, and No. 10 Pablo Carreno Busta, who was leading 6-2, 3-0 when Gilles Simon retired from their second-round match with a thigh injury.
No. 23 Gilles Muller outlasted Malek Jaziri in five sets, Kyle Edmund had a straight-sets win over Denis Istomin -- who beat then defending-champion Novak Djokovic in the second round here last year -- and No. 30 Andrey Rublev beat Marcos Baghdatis.
Information from The Associated Press was used in this report.