The 21st seed took three hours and 50 minutes to eliminate Sonego 6-4 7-5 4-6 7-6 (7-4) in Wednesday's gruelling quarter-final.
In a rollercoaster fourth-set tiebreaker, Shelton failed to lose another point after crashing into the advertising boards, getting up from the ground via a push-up.
Ben Shelton takes a tumble into the signboards on his way to victory against Sonego. (AP PHOTO)
Showman Shelton roared after securing the victory, then passionately celebrated with members of his box.
It will be Shelton's second major semi-final, after previously making the final-four at the US Open in 2023.
"I feel relieved right now," Shelton said.
"Shout-out, Lorenzo Sonego, because that was some ridiculous tennis.
"I'm just really happy to be through and get my first win here on Rod Laver Arena ... that's one of my favourite matches of my career."
Shelton, who emerged as a young gun of world tennis when he made the quarter-finals of the 2023 Australian Open, will face world No.1 Jannik Sinner or local hope Alex de Minaur in the semi-finals.
"You guys can boo me, you can throw stuff in my head, I understand," a grinning Shelton said about the prospect of playing de Minaur.
Ranked 55, Sonego had previously never made it past the fourth round at a grand slam.
Despite playing a wildcard and two qualifiers in three of his first four matches at the Open, Sonego threatened to take Shelton to a fifth and deciding set after dropping the first two.
Ah, what... How did the ball end up there?!— #AusOpen (@AustralianOpen) Not for the first time at #AO2025, Lorenzo Sonego wins a crazy point!@wwos • @espn • @eurosport • @wowowtennis pic.twitter.com/UifdSZjdEzJanuary 22, 2025
In a rare mid-match display of camaraderie, Shelton shook hands with Sonego at the end after an extraordinary point.
Sonego pulled off an unplayable backhand volley, diving to return an attempted passing shot, with the ball spinning away from Shelton after bouncing to the other side of the net.
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