World number one Jannik Sinner played through a fire alarm to beat Gabriel Diallo and reach the fourth round of the Cincinnati Open.

The alarm began to sound and lights started flashing in the second game of the second set but the pair agreed to play through it after a delay of several minutes.

Sinner, 23, remained composed and booked his spot in the last 16 with a 6-2 7-6 (8-6) victory against the Canadian.

“It was a very difficult day at the office,” Sinner said.

“You have to find the balance against these big servers. I struggled with that at times today.

“But I need tough matches like this, I’m happy I got one before the [US Open] Grand Slam.”