The two-time defending champion had endured a testing third-round match on Saturday afternoon, struggling with extreme heat and cramping against world No. 85 Eliot Spizzirri, News.Az reports, citing AP.
Sinner only gained control of that contest after officials closed the roof during the third set.
Sinner later acknowledged that he benefited from the timing of the tournament’s extreme heat policy, which allowed for an eight-minute pause to close the roof, as well as an additional 10-minute cooling break between the third and fourth sets.
Playing under cooler evening conditions on Monday, the world No. 2 was largely in control before Darderi raised his level in the third set. Sinner missed match points in the 10th game on his opponent’s serve but ultimately sealed the win 6-1, 6-3, 7-6 (7-2) to book his place in the last eight.
Darderi, who saved two match points on his serve, took the first two points of the tiebreaker but then had to pause for a few moments before serving because of a baby crying in the crowd at Margaret Court Arena.
He didn’t win another point, with Sinner reeling off the next seven to triumph in 2 hours and nine minutes.
It extended his unbeaten streak to 18 against other Italians on tour and earned a quarterfinal against No. 8 Ben Shelton or No. 12 Casper Ruud.
Sinner had 19 aces — a personal record — and no double-faults and said he was satisfied with the work he put into his serve over the offseason.
He also wanted to emphasize some minor changes to his game, including going to the net and trying to mix up his game.
In a tough hold in the third set, Sinner saved a breakpoint by changing the direction of the rally with a forehand drop shot, bending his knees low to win the point. He serve-and-volleyed to hold that game.
“Still room to improve, but very happy with how I’ve come back,” he said. “Now for sure, it (the serve) is a bit more stable. I try to go more to the net and being more unpredictable.”
