Looking more settled in Vienna, the fifth-seeded Tiafoe began the week with a straight-set win over former Indian Wells champion Cameron Norrie to book his clash with Berrettini, who was equally decisive in his opener against Marton Fucsovics.
Berrettini saved a break point in the opening game and ultimately clinched the lone break of the first set, serving it out at love in under 40 minutes. The 28-year-old navigated an even more dramatic opening serve game in the second set and appeared to have the match all wrapped up when he broke Tiafoe to open up another 5-3 advantage.
Tiafoe turned the tables on the Italian in the 10th game, breaking Berrettini from match point down and forcing a Sudden Death two games later.
Again, Tiafoe was on the back foot, trailing Berrettini 2-5 and another two match points. Saving both, the American reeled off six of the tiebreaker’s final seven points to push the match to an improbable decider.
The duo exchanged breaks to kick off the third set, and the finale played out similarly to the second: Berrettini opened up a big lead only for Tiafoe to threaten a comeback. This time, Tiafoe looked to come back from 5-2 down, pressuring Berrettini at the net when the Italian earned a fourth match point. But Berrettini made no mistake on the fifth, forcing a forehand error from the American to edge over the finish line just after three-hour mark.
Standing between the former world No. 6 and a spot in the semifinals will be either countryman Brandon Nakashima or Almaty Open champion Karen Khachanov.
