AITOR KARANKA

questioned his Birmingham side’s effort after their awful home form continued.

Dan Potts scored the only goal to sentence the club to an 11th home game without a win, less than 24 hours after chief executive Xuandong Ren said Karanka had the board’s ‘100 per cent’ backing.

‘The effort concerns me because we knew Luton were good at long and second balls and when they won every second ball it means they had more effort,’ he said.

Luton boss Nathan Jones said: ‘I felt it was deserved. I felt we restricted them to little.’