Tranmere kept their Vanarama National League play-off semi-final hopes on track with a 2-0 victory at struggling Chester.Goals from Andy Cook and James Norwood sent Micky Mellon's side up to fourth, just a point adrift of automatic qualification through to the semi-finals with two games in hand.Rovers made a promising start and Norwood saw a header come back off the crossbar just eight minutes into the contest.But Tranmere did go ahead in first-half stoppage time when Jeff Hughes' cross picked out Cook and he made no mistake in heading past Andy Firth.Norwood made the game safe in the 64th minute when he latched onto a ball from the back to round Firth and roll the ball into the net.