The Red Devils confirmed that there were no injuries and the blaze was quickly brought under control with minimal damage.
Manchester United have confirmed that fire crews attended an incident at Old Trafford in the early hours of Monday morning.
Local media outlets reported that there was an incident at the Theatre of Dreams that required the fire brigade to be called, but the club have acted swiftly to play down the severity of the episode.
The club released a statement on their Twitter feed, which read: “A small electrical fire was identified quickly in the Sir Bobby Charlton stand around 7am today.
“The fire brigade attended & the isolated incident was dealt with quickly & effectively. There was minimal damage & there were no injuries.”
Earlier, Greater Manchester Fire and Rescue Services had told the Manchester Evening News : “We were called at 6.58am to Sir Matt Busby Way.
“Three fire engines from Manchester, Salford and Stretford attended the scene.
“We have isolated the electrics and extinguished the fire using breathing apparatus and a CO2 fire extinguisher.”
Reports suggest that the fire started in the motor room of the stand.
Jose Mourinho’s men will see this as an unwelcome distraction ahead of their midweek home Premier League encounter against Hull City, in which they will try to get their top four push back on track after stumbling to a 1-1 draw against Stoke last week.
Since then, they were defeated Hull in the first leg of their EFL Cup semi-final but beat Wigan in the FA Cup fourth round at the weekend.