Shelton, who reached the semi-finals last year before falling to eventual champion Jannik Sinner, dominated the first set, but the Frenchman pushed back in sets two and three, forcing tiebreaks. It was there that the American’s experience at Melbourne Park—he played eight tiebreaks across six matches last year—proved decisive.

“I thought I just played two great tiebreakers. I’ve played a lot of tiebreakers here, and that experience helped me a lot today,” Shelton said.

The American set the tone early, firing a 229kph serve on just the second point of the match and breaking quickly to move 3-1 ahead. One blistering delivery struck Humbert on the arm, drawing an immediate apology from Shelton, but his intent was clear as the Frenchman struggled to cope with the sustained pace.

Shelton also produced a moment of brilliance when he squeezed a seemingly impossible return between a ball kid and the net post, later sealing the set with a sharp crosscourt forehand winner.

Humbert, having been under pressure for 75 minutes, rallied in the second set. The pair traded breaks, and Shelton’s unforced errors mounted, allowing Humbert to recover and force a tiebreak. Yet when it mattered most, Shelton’s precision returned, and he raced through to a two-set lead.

The third set evolved into a serving duel, with both players holding firm. Break points were rare, and the set headed to a second tiebreak. Humbert surged to a 3-0 lead, but Shelton fought back, ultimately clinching the match with a forehand winner down the line on match point, handing Humbert his first loss in four Grand Slam encounters against a left-hander.

“I thought I stayed really calm today… Playing Ugo in the first round is a tough draw,” Shelton said. “I felt like I found some of my better tennis later in the match. I’m looking forward to building on this form and improving as the tournament goes on.”