"It was an incredible match and it could have gone both ways," Ruud said.

"Max has taken his tennis to a new level and I wish him the best of success in the year to come.

"He plays fast and is one of the most unorthodox players these days. It's tough. He made it hard and luckily in the end it went in my favour."

Alcaraz was tested by blustery conditions and a tricky opponent in Sonego but he was able to keep the world number 46 at bay in the fourth set tie-break to seal victory in three hours and 25 minutes.

It is just the second time Alcaraz, a two-time major winner, has reached the third round in Melbourne, having missed last year's tournament through injury.

"I'm really happy with my performance today," said the Spaniard, who will next face Chinese wildcard Shang Juncheng.

"I think both of us played at a really high level, with high intensity. The match was a little bit tricky with the wind and the sun.

"It was tough to play your best but we tried to stay there all the time, even if I lost the second set."