Ben Shelton battled to a four-set win over Lorenzo Sonego to reach his second grand slam semi-final.

The big-serving American made his breakthrough at the Australian Open two years ago with a run to the quarter-finals on his debut before bettering that at the US Open.

The draw at Melbourne Park has opened up for the 22-year-old and he has taken full advantage, with his latest triumph a 6-4 7-5 4-6 7-6 (4) victory over unseeded Italian Sonego.

Sonego, ranked 55 and playing in his first slam quarter-final, attacked the net repeatedly and threatened to take the contest to a deciding set.

Shelton showed his desire during the fourth-set tie-break by hurling himself across the court in an effort to retrieve a volley. After lying sprawled by the advertising hoardings, he showed he was still fighting fit with a press up.

And moments later Shelton was roaring with delight after booking a last-four spot, where he will face either world number one Jannik Sinner or home favourite Alex De Minaur.

“I feel relieved right now,” said Shelton. “Shout out to Lorenzo Sonego because that was some ridiculous tennis. I’m really happy to be through, get my first win on Rod Laver Arena. It’s one of my favourite matches of my career.”