Daniil Medvedev of Russia in action. Photo / AP

Two-time losing finalist Daniil Medvedev fired up his bid to go one better at the Australian Open with a straight-sets demolition of Marcos Giron on Monday night.

The Russian seventh seed, almost a foot taller than his opponent, blasted past the 56th-ranked American 6-0 6-1 6-2 on Rod Laver Arena in just 1hr 36mins.

There was barely a hiccup until Medvedev was taken to deuce while trying to serve for the match.

The tension prompted the combative star to object to one rowdy fan, who he promptly told to “f*** off”.

The chair umpire immediately gave Medvedev a code violation for audible obscenity, which drew a shake of the head from the 26-year-old.

Medvedev lashed out at the Melbourne crowd during the final last year, which he lost to Rafael Nadal despite taking the first two sets.

“They are idiots. No brains, empty brains,” he said in a conversation with the chair umpire at a change of ends. “Probably in their life, it must be very bad.”

He then delivered an angry rant in his post-final press conference, calling the crowd “disrespectful”.

“A thousand people would be like, ‘Tsss, tsss, tsss’. That sound. It’s disappointing. It’s disrespectful,” he said. “I’m not sure after 30 years I’m going to want to play tennis.”

Next up for Medvedev is a second-round clash with Australian wildcard John Millman, who came through a five-setter against Switzerland’s Marc-Andrea Huesler.

Nadal overcomes wobble

Rafael Nadal launched his Australian Open title defence with a four-set victory over Britain’s Jack Draper on Monday as home hope Nick Kyrgios quit through injury without hitting a ball.

In the women’s draw, top seed Iga Swiatek survived a tough examination while Jessica Pegula and teenage prodigy Coco Gauff were both emphatic winners on the first day of action.

Spanish great Nadal, 36, had been in poor form by his sky-high standards, losing six of his last seven matches stretching back to defeat in the last 16 at the US Open.

In fast-rising Draper, 21, the 22-time Grand Slam champion faced a stern test to start his campaign at a sweltering Melbourne Park.

The top seed recovered from a second-set wobble — and a bizarre incident when a ball boy accidentally took his racquet — to defeat the 38th-ranked Briton 7-5 2-6 6-4 6-1 at Rod Laver Arena.

Nadal, who recently became a father, faces American Mackenzie McDonald in round two.

“Very exciting, new beginning, just super-happy to be back at Rod Laver with a victory I needed,” he said after grinding down Draper. “Last couple of months have not been easy for me.”

Nadal was on court when Australia’s talented but temperamental Kyrgios called a hastily arranged press conference and announced that he was out of the tournament with a knee injury.

“I’m devastated, obviously,” said the Wimbledon finalist, who was considered an outside bet to win a maiden Grand Slam crown.

“I’ve had some great tournaments here, winning the doubles last year and playing the tennis of my life probably going into this event.

“I’m just exhausted from everything, and (it’s) obviously pretty brutal.”

The first Grand Slam of the year had already lost several stars in the build-up. Injured men’s world number one Carlos Alcaraz and two-time Melbourne champion Naomi Osaka — who is expecting her first child — are among the other players missing.

Other winners on Monday included third seed Stefanos Tsitsipas and sixth seed Felix Auger-Aliassime, who saw off dogged Vasek Pospisil in an all-Canadian clash.

In the women’s draw, hot favourite Swiatek was far from her fluent best against Jule Niemeier but got the job done, 6-4, 7-5.

The Pole, who is chasing an Australian Open crown to go with major titles at the US Open and Roland Garros, plays Camila Osorio of Colombia next.

In-form Pegula blitzed 161st-ranked Romanian Jaqueline Cristian 6-0, 6-1 in a 59-minute romp to signal her intent.

Fellow American Gauff was equally explosive in racing into the second round with a 6-1, 6-4 thumping of Czech Katerina Siniakova.

The 18-year-old Gauff now faces a mouth-watering encounter against former US Open champion Emma Raducanu.

Also safely through was another American, Danielle Collins, last year’s beaten finalist in Melbourne.

Greek sixth seed Maria Sakkari also won and Victoria Azarenka defeated Sofia Kenin in a battle of two former Australian Open champions.