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Play was halted in the second game of the second set in his third-round match with Gabriel Diallo when a fire alarm in the 1899 club grandstand began to sound. After a delay of several minutes, the players agreed to play through the sound and flashes, playing four points before the alarm ended. 

Sinner ultimately closed out the match 6-2, 7-6(6) after saving a set point with a clutch forehand service return in the tie-break.

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

The start of Sinner’s evening match had been delayed by a late finish to Taylor Fritz’s match with Lorenzo Sonego, which endured a 75-minute delay when the venue lost power.

Sinner took the first set 6-2 against the World No. 35, 6’ 8” Canadian in their first meeting after winning six straight games from 0-2 in the first set. Diallo pushed Sinner to a tie-break on the strength of his first serve but came undone in the tie-break when he made just two of seven first serves. For the match he won just five of 32 second-serve points against the four-time major champion.

Diallo had a set point at 6-5 in the tie-break but after landing just his second first serve of the 'breaker he was unable to deal with a scorching Sinner forehand return that landed at his feet.

Sinner is on a 22-match hard-court winning streak since losing to Carlos Alcaraz in the Beijing final in October. He improved to 46-0 against players ranked outside Top 20 on hard courts since losing to World No. 66 Dusan Lajovic at this tournament two years ago.

Diallo, who played college tennis at the University of Kentucky, just two hours from the Lindner Family Tennis Center, home of the Cincinnati Open, fired 10 aces but also threw in a career-high 10 double faults as he perhaps tried to overplay against Sinner.

Sinner, who has reigned at No. 1 in the ATP Rankings for 61 consecutive weeks since becoming the 29th man to rise to top spot, next plays Adrian Mannarino, who defeated Tommy Paul 5-7 6-3 6-4.

Playing his first tournament since winning his first Wimbledon title, Sinner is 27-3 on the season. Just 10 wins away from 300 career wins, Sinner earlier in the tournament became the second player to qualify for November's ATP Finals, where he will be the defending champion.