Unai Emery fears Arsenal captain Laurent Koscielny may have broken his jaw during the 3-1 defeat to Manchester United in the FA Cup.

United ran out comfortable winners thanks to goals from Alexis Sanchez, Jesse Lingard and Anthony Martial but to make matters worse for Emery, Koscielny and his centre-back partner Sokratis were both forced off with injuries.

Sokratis limped off in the opening period with the scoreline at 0-0 after landing awkwardly on his ankle during the fourth-round clash.

And in the second half, Koscielny – who just worked his way back into the team after recovering from a long-term ruptured Achilles injury – was seen to by Arsenal’s medical staff on the floor for around 10 minutes with what appeared to be an injury to his jaw.

And after the defeat to their historic rivals, Emery confirmed Koscielny is being sent to hospital for checks on what he believes could be a broken jaw.

The despondent Gunners boss said: “I think it is not a big injury for Sokratis - it is his ankle.

“Laurent Koscielny is maybe going to the hospital for analysis to find out what injury he has. Maybe he has broken his jaw. I hope not but we have to wait.”

Emery is now set to have a selection headache at the back when Arsenal take on Cardiff at the Emirates on Tuesday night in the Premier League.

The Spaniard will hope his players respond in style next week as they look to avoid their domestic season petering out and ending in disappointment.