Michael Stewart’s second-half penalty was enough to send Hearts through to the semi-finals of the Co-operative Insurance Cup and heap more pressure on Celtic boss Tony Mowbray.

Celtic’s Danny Fox was penalised for fouling Christian Nade early in the second period and despite Stewart firing his penalty straight at Lukasz Zaluska the ball crept over the line.

The hosts responded positively but striker Georgios Samaras was guilty of missing several chances, although the Greek frontman did hit the woodwork as did Pat McCourt.

Things turned from bad to worse for Mowbray in time added on as captain Stephen McManus was shown the red card for cynically bringing down Andrew Driver.

Celtic have won just two of their nine home games this season and left the field to o a chorus of boos from supporters.