The Canadian Open semi-final between Ben Shelton and Taylor Fritz descended into farce before the pair even started their match in Toronto. After Karen Khachanov shocked top seed Alexander Zverev, the two Americans were preparing to go head-to-head for a place in the final.

They were warming up at Sobeys Stadium when they were ordered to halt proceedings. After discussions with officials, both Shelton and Fritz headed back to the locker rooms after being told their match was being delayed. The rivals emerged some 20 minutes later to finally get going in front of a restless crowd.

The problems were due to issues with the electronic line-calling system. Without backup line judges to replace the technology failure, the match could not start until the system was fixed.

Fans and pundits on social media criticised the bizarre delay. Renowned tennis journalist Jose Morgado posted on X: "It's unbelievable. Especially in a day with only one court in play. Amateurish stuff."

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When it did get underway, it was world No.7 Shelton who went on to upset his higher-ranked compatriot. He prevailed 6-4 6-3 and is now within one win of the first ATP 1000 Masters title of his career.

However, afterwards, a delighted Shelton chose not to focus on the controversy, celebrating by writing on a TV camera: “Even more uncharted territory. Humble and Hungry.”

It’s not the first time that a professional tennis tournament has been plagued by controversy over technology this year. At Wimbledon, an ‘operator error’ meant the ball-tracking technology was turned off for one game in the fourth-round match between Britain's Sonay Kartal and Russian Anastasia Pavlyuchenkova.

Kartal sent a backhand long, but the line-call system did not detect it and instead made two automated calls of ‘stop’. Umpire Nico Helwerth opted to replay the point, but was criticised by Pavlyuchenkova for not overruling and calling the ball out.

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