Wimbledon chiefs on Monday blamed human error for an embarrassing failure of the tournament's electronic line-calling system.
Officials apologised to Anastasia Pavlyuchenkova and Sonay Kartal after the malfunction during their fourth-round match on Centre Court on Sunday, which Pavlyuchenkova won in straight sets.
After an investigation, organisers admitted the technology was turned off in error on a section of the court for a game, with the mistake only becoming apparent when a shot from Britain's Kartal that clearly missed the baseline was not called out.
Had the call been correct, it would have given Russia's Pavlyuchenkova a 5-4 lead in the first set, but instead umpire Nico Helwerth ruled the point should be replayed, with Kartal going on to win the game.
The Russian accused the official of home bias, saying: "Because she is local, they can say whatever. You took the game away from me."
Wimbledon issued a statement on Sunday saying the system had been "deactivated in error" for one game by those operating the system.
"In that time, there were three calls not picked up by live ELC on the affected part of the court. Two of these were called by the chair umpire, who was not made aware that the system had been deactivated," it said.
"Following the third, the chair umpire stopped the match and consulted with the review official. It was determined that the point should be replayed.
"The chair umpire followed the established process. We have apologised to the players involved."
Sally Bolton, chief executive of the All England Club, told reporters on Monday that the system was "working optimally."
"The issue we had was human error in terms of the tracking system having been inadvertently deactivated, and then the chair (umpire) not being made aware of the fact that it had been deactivated," she said.
She added: "We've spoken to the players, we've apologised to them, we've very quickly moved into reviewing everything that had happened yesterday afternoon and putting in place the appropriate changes to the processes."
A fully automated system has replaced human line judges at Wimbledon in 2025, in line with the Australian Open and the US Open.
But the glitch in Sunday's fourth-round match follows concerns raised by other players about the technology, including British stars Emma Raducanu and Jack Draper.
Around 80 former line judges are employed as match assistants, with two on each court offering support to the umpire.
But Bolton said there was no need to put them back on the courts.
"The system was functional," she said. "It had been deactivated. We didn't need to put line judges back on the court again, we needed the system to be active."
Automated line-calling technology has become standard across tennis, with all events on the men's ATP Tour and many WTA tournaments using it.