Forced to miss last year's Australian Open because of injury, Wimbledon champion Alcaraz dominated French veteran Gasquet on his return to Melbourne Park in a 7-6 (7-5) 6-1 6-2 win.

The 20-year-old Spaniard, who at his past four Grand Slams has won two titles and reached two semi-finals, is aiming to significantly improve his record in Melbourne - where he has not gone beyond the third round in two previous appearances.

Alcaraz remained patient when faced with stern resistance from the 37-year-old Gasquet - playing the 23rd season of his career - who saved nine break points to force a tie-break in an entertaining opening set.

But, after edging the tie-break from 5-4 down, Alcaraz's quality shone through - although Gasquet forced him to wait until his fifth match point to finally clinch a victory which set up a second-round meeting with Italian Lorenzo Sonego, who beat Briton Dan Evans.

Elsewhere, Danish eighth seed Rune beat Yoshihito Nishioka 6-2 4-6 7-6 (7-3) 6-4 in what he called a "physical battle".

German sixth seed Zverev, meanwhile, had to come from behind to beat compatriot Dominik Koepfer 4-6 6-3 7-6 (7-3) 6-3.

The win came the day after German court officials set a date for his trial over domestic abuse allegations, which he denies.

Bulgarian 13th seed Grigor Dimitrov - fresh from winning his first ATP title since 2017 in Brisbane - also advanced, coming back to beat Marton Fucsovics 4-6 6-3 7-6 (7-1) 6-2.

Meanwhile, 26-year-old Nagal will get the chance to further improve his bank balance - reaching the third round brings prize money of 133,000 - when he takes on Chinese world number 140 Shang Juncheng, who is ranked three places below him.

He said he was not thinking about expectations back home, saying: "I want to go through this moment, take my time, enjoy being with my coach, have conversation, maybe eat a burger or something, and call it a night."