Australian Open 2019: Roger Federer and Rafael Nadal through, John Isner out

Federer is a 20-time Grand Slam champion

Defending champion Roger Federer is into the Australian Open second round after beating Uzbek Denis Istomin.

The Swiss, who has won the tournament six times, came through 6-3 6-4 6-4 and will play Britain's Dan Evans next.

Meanwhile, 17-time Grand Slam winner Rafael Nadal beat James Duckworth 6-4 6-3 7-5 to reach the second round.

John Isner became the first top-10 player to fall on the opening day as he was stunned in four sets by world number 97 Reilly Opelka.

American Isner, seeded ninth in Melbourne, was beaten 7-6 (7-4) 7-6 (8-6) 6-7 (4-7) 7-6 (7-5) by compatriot Opelka in just over three hours.

The victory was Opelka's first in the main draw of a Grand Slam.

Opelka - who at 6ft 11ins is the joint-tallest player on the ATP Tour - is the first American to beat 6ft 10ins Isner at a Slam.

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South African fifth seed Kevin Anderson also progressed by beating France's Adrian Mannarino 6-3 5-7 6-2 6-1.

The 32-year-old, who has reached the fourth round at Melbourne Park on three occasions, served 14 aces but made 38 unforced errors as he won his opening match in two hours and 53 minutes.

The Wimbledon runner-up faces American Frances Tiafoe in the next round.

I'll give it my best shot - Federer

Federer, who is taking part in his 20th Australian Open, won in just under two hours.

The 37-year-old did not face a break point against Istomin, 32, as he started his campaign for a third straight title in Melbourne.

"I'm very happy with the match," said Federer. "I brought good energy and I played some good shots. I was solid overall because Denis made it tough.

"It's disbelief to be quite honest that I'm the double defending champion at my age.

"I hope I can do it again this year. I have to go in with a mindset that it's maybe possible - but it's probably going to be somebody else.

"I'm going to try everything that I possibly can. I'm going to leave it all on the court and then we'll see what happens. I'll give it my best shot."

Nadal's new serve 'worked well'

Spanish second seed Nadal, 32, saw off Australian Duckworth in two hours and 16 minutes on Rod Laver Arena, despite a stubborn finish from Duckworth.

"He was playing super aggressive, every shot," said Nadal.

Nadal, who cut short his 2018 season with an abdominal muscle injury and to have ankle surgery, appeared to be back to full fitness against wildcard Duckworth.

The world number two showed no sign of being bothered by a thigh strain that had forced him to pull out of the Brisbane International earlier this month.

He was delivering a remodelled serve, which worked well even if he was broken to love when serving for the match at 5-3 in the third.

"When I get broken [it] was not because of the serve," he said.

"When you play against a player that wants to hit all the shots, of course you can have breaks against, because you are sometimes in his hands,

"But anyway, my serve worked well. I don't know my percentage, but [there were] a lot of good positions after the first serve. I felt solid with the second."

He won 74% of first-serve points and delivered six aces.

Nadal will play Australian Matthew Ebden in the second round.

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