Jannik Sinner ignored power failure interruptions and a blaring alarm to defeat Gabriel Diallo 6-2, 7-6 (8/6) day of distractions at the ATP and WTA Cincinnati Open.

The top seeded defending champion got down to business against a Canadian ranked 35th who was plagued by eight first-set double-faults and 49 unforced errors in the match as he faced the best in the world.

Sinner recovered smoothly from an early break down and had his hands full on his way into the fourth round, sending over an ace on match point after saving a set point in the tiebreaker.

Play was stopped briefly with Sinner leading 4-2 as the audio portion of the electronic line-calling system suddenly failed.

Earlier, both players had to deal with flickering LED screens directly behind them courtside.

The pair agreed to soldier on without the system, with the chair umpire temporarily relaying the algorithm's decisions – which he saw on his chair's tablet – to the players when necessary as a re-boot was undertaken.

That minor malfunction came two hours after the chaos of a widespread power outage which completely stopped play around the grounds for 75 minutes.

Five minutes later, with Sinner leading 1-0 in the second set after winning the first, the chaos continued with an alarm going off somewhere in the stadium and play suspended for the third time.

Sinner and Diallo continued to carry on with the distraction blaring somewhat faintly in the background before it finally halted after another game.

Sinner polished off victory for his 23rd consecutive hardcourt win in under two hours.

"It was a very difficult day at the office," the Italian 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 Grand Slam," he added. "I'm happy about today, but I know I can do things better."

US fourth seed Taylor Fritz endured a one-hour delay after the first set before defeating Lorenzo Sonego 7-6 (7/4), 7-5 for a 21st win in 25 matches.

"I can play better, but there has been no time to really train and get ready," Fritz said. "I'm looking forward to fine tuning the week before the US Open."

Compatriot Frances Tiafoe advanced past Ugo Humbert of France 6-4, 6-4 in 82 minutes and lines up next against Holger Rune, who beat Alex Michelsen 7-6 (7/4), 6-3. (AFP)