Last updated on .From the section Tennis

Rafael Nadal and Victor Estrella Burgos share a joke at the end of their match

2018 Australian Open Dates: 15-28 January Venue: Melbourne Park Coverage: Watch highlights on BBC Two, the BBC Sport website and app. Live commentary on the best matches on BBC Radio 5 live, 5 live sports extra and online.

World number one Rafael Nadal powered into the Australian Open second round with a routine win over the Dominican Republic's Victor Estrella Burgos.

The Spaniard, playing his first tournament match since suffering a knee injury in November, won 6-1 6-1 6-1 in 94 minutes on Rod Laver Arena.

Nadal, who is aiming for a 17th Grand Slam title and a second in Australia, said his knee was "feeling good".

"If I did not feel ready I would not be here. I'm happy to be back," he said.

"I always have doubts, but at the same time I have confidence that I was ready to start the tournament and that was the case."

The injury forced Nadal to miss this month's Brisbane International, and he only had a one-match workout at the exhibition Kooyong Classic before heading into the first Grand Slam event of the year.

But the Spaniard, who was beaten by Roger Federer in last year's final, got off to a perfect start and raced to victory over the 37-year-old.

The world number one will play Leonardo Mayer of Argentina next.

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This is the 52nd Grand Slam of Nadal's career but the first without his long-time coach and uncle Toni Nadal in his box.

Toni announced last season that he would cease to travel with his nephew at the end of 2017 to focus on the family's academy in Majorca.

"Toni is the most important person in my career, everybody knows," said Nadal, who is now coached by former world number one Carlos Moya.

"I can't thank him enough for all the things but today he is not here. He's doing a great job in my tennis academy. I have to think about the team that is here. I am happy with it."

Dimitrov wins but Sock goes out

Third seed Grigor Dimitrov and in-form Australian Nick Kyrgios also advanced, but eighth seed Jack Sock was one of 12 Americans in the men's and women's singles draws to lose.

Sock went down 6-1 7-6 (7-4) 5-7 6-3 to world number 41 Yuichi Sugita, and 16th seed John Isner lost 6-4 3-6 6-3 6-3 to Australia's Matthew Ebden.

Fifth seed Venus Williams, 10th seed Coco Vandeweghe and US Open champion Sloane Stephens were all knocked out of the women's event.

Bulgarian Dimitrov, 26, went through with a 6-3 6-2 6-2 win over Austrian Dennis Novak in one hour 38 minutes.

Kyrgios, the top-seeded Australian in the men's draw at 17, enjoyed a straightforward 6-1 6-2 6-4 victory over Brazil's Rogerio Dutra Silva.

Croatia's sixth seed Marin Cilic beat Canadian qualifier Vasek Pospisil 6-2 6-2 4-6 7-6 (7-5).