The world number four rallied from two sets down at Rod Laver Arena to stun 2021 U.S. Open champion Daniil Medvedev 3-6, 3-6, 6-4, 6-4, 6-3 and claim his first major.
"We believe in Jannik, we always have. He's a special young kid," Cahill said. "Even the way he hits the ball, it just sounds special.
"He's absorbing everything and trying new things on the court, and he just wants to get better. I'm sure after this sinks in he won't settle. He'll never settle. He wants to get better."
Sinner and Carlos Alcaraz,(20) are spearheading a new generation of talent trying to loosen Novak Djokovic's grip on the Grand Slams. Alcaraz already has two major crowns to his name and Cahill said Sinner is "chasing" the Spaniard.
"Carlos has trail-blazed for a lot of young players. We're thankful for that. He's a delight to watch play and a delight to watch him on court," he added.
"We aspire to be as good as him and hopefully one day be better than him, but at the moment we're chasing Carlos, and we'll continue to do that."
