unbeaten championship leaders leigh delivered a stunning knockout blow as super league club salford crashed out of the ladbrokes challenge cup .
the centurions twice came from behind in thrilling fashion to beat the red devils 22-18 in front of a 6,358 crowd at leigh sports village and stretch their winning run to 21 matches .
the build-up to the fifth-round tie was dominated by the selection by leigh of former england forward gareth hock despite an agreement not to play against his old club .