But struff

Infosys ATP Stats: World No.1 Jannik Sinner survived a strong challenge from a brilliant serving from Jan-Lennard Struff to advance into the semifinals of the Halle Open tennis tournament on Friday. Struff hit 18 aces and saved 16 of 18 break points -— including all 11 in the second and third sets -— but could not pull off the upset against the new No. 1 in the ATP Rankings.

The Italian's 6-2, 6-7(1), 7-6(3) result was his third consecutive three-set win in Halle, after earlier victories against Tallon Griekspoor and Fabian Marozsan. Sinner lost a tie-break in each of the three matches.

Playing in his first event as World No. 1, Sinner has yet to meet a seeded opponent. That trend will continue in Saturday's semis when he takes on Zhang Zhizhen or Christopher Eubanks. Sinner is bidding to become the eighth man in ATP Rankings history to win the title in his first event as No. 1, and the first to do it since Andy Murray at the 2016 ATP Finals.