Sinner wins the first two sets against Berrettini 6 (3) and 6 (4). It looked like Matteo was going to win the second set after he broke Jannick for 4-2, but Sinner broke right back and got to the breaker.
I thought that Sinner was experiencing a lull in the second set around the time he got broken, but the third set was even more worrisome as Berrettini takes it 6-2.
4th set: Sinner's doldrums continue and get more serious as Berrettini nabs the first break for 2-1. The longer this malaise continues the more one worries that there is something physically wrong with Jannick....but Berrettini, who has never beaten a player ranked #1 in four previous attempts, once again can't convert, and the set is 2-all....another breaker and another win for Sinner, 7-6, 7-6, 2-6, 7-6. That was a challenge for Sinner, for sure.