There was chaos at the US Open when officials in the hawkeye base were evacuated from their offices.

Employees working in the hub of the electronic line calling system abandoned their positions when a fire alarm went off.

It meant matches were temporarily paused with the players forced to wait on court while the system was down.

Caroline Wozniacki and Beatriz Haddad Maia were in the middle of the first set of their fourth-round match when calls of "stop" were suddenly heard from the court. The chair umpire tried to find out what was going on as play was halted.

And it quickly transpired that the building home to the team running the official hawkeye system had been evacuated. "Well the fire alarm is going off literally here in front of our production office, the fire alarm is going off there and people are getting evacuated," Naomi Cavaday said on Sky Sports commentary.

Wozniacki and Haddad Maia quickly rushed to the net and the umpire explained the issue to the crowd. "Ladies and gentlemen, the system is down for the moment so we will hold the play shortly," Marijana Veljovic announced.

Behind-the-scenes footage showed empty chairs in the hawkeye office as the fire alarm forced play on every single court to be suspended. Wozniacki paced around the Louis Armstrong Stadium and declared: "This is a first."

On commentary, Cavaday continued: "So all of the members of the hawkeye team that are running the electric line calling system, they’ve all been asked to leave the building and evacuate which means we have no hawkeye system which means nobody calling the lines.

"Umpire can’t do it by herself so we’re just going to have to wait for the system to come back or, if it’s going to be a while, maybe find some line judges."