Jannik Sinner Vs Gabriel Diallo, Cincinnati Open: World No. 1 Navigates 'Difficult Day' To Enter Last 16

Jannik Sinner overcame Gabriel Diallo to take his place in the last 16 of the Cincinnati Open.

World number one Sinner, who triumphed in Cincinnati last year prior to winning the US Open, prevailed 6-2 7-6 (8-6) on Monday.

Sinner did not have it all his own way, and had to save a set point in the second, while play was also halted for seven minutes due to a fire alarm in the stadium.

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

"He was serving very well, especially in the second set. If you don’t play well in tough situations like this you can lose these matches."

Next up for Sinner is qualifier Adrian Mannarino, who came from a set down to shock Tommy Paul 5-7 6-3 6-4.

Joao Fonseca also slipped out, losing 6-3 6-4 to Terence Atmane.

Reward for Atmane's victory is a meeting with fourth seed Taylor Fritz, who got the better of Lorenzo Sonego 7-6 (7-4) 7-5 in a match delayed due to a loss of power at the venue.

Nothing could separate the duo during the opening set – Fritz winning 14 successive points on serve along the way – with the American eventually recovering from 3-1 down in the tie-break to draw first blood.

He maintained that momentum into the second, though it took until the penultimate game for him to finally clinch the vital break needed to avoid another tie-break.

Last year's runner-up Frances Tiafoe also progressed, defeating Ugo Humbert 6-4 6-4 to tee up a showdown with Holger Rune, who was a 7-6 (7-4) 6-3 winner over Alex Michelsen.

Data Debrief: Hard-court specialist Sinner matches big four

Sinner is now the fifth player to claim at least 23 straight hard-court wins on the ATP Tour in the 21st century, after Roger Federer, Rafael Nadal, Andy Murray and Novak Djokovic.

His next opponent, Mannarino, has become the second-oldest qualifier to reach the last 16 at an ATP Masters 1000 event. At the age of 37 years and 39 days, the Frenchman is younger than only Radek Stepanek (37y 240d, Toronto 2016).