Live updates from the fourth round at Flushing MeadowsMatch report: Williams hits top gear to deny SakkariLine judge hit by Djokovic receives abuse on social mediaDrop Simon an email or tweet @Simon_Burnton 9.55pm BST
Thiem has broken Auger-Aliassime in the first game of the third set, and the 20-year-old Canadian is in very deep trouble now. Indeed, his trouble has just got a little deeper as Thiem has held to 15, making it 7-6, 6-1, 2-0 on Arthur Ashe. 9.53pm BST
Next up on Armstrong is Matteo Berrettini, the Italian sixth seed, against Russia’s No10 seed Andrey Rublev. As it happens the pair met at the same stage of last year’s
US Open, with Berrettini winning. The Italian is 3-1 up in the head-to-head, and every match has been won in straight sets.