Mariner made his debut in September 1976 and quickly settled into the Ipswich side as an old-fashioned number 9 – i.e., a forward capable of taking hard tackles and rough treatment from defenders but willing to give it back, while also scoring a fair share of goals. Received wisdom suggests that Mariner was only a 'target-man'-type centre forward but he scored plenty of goals with his feet and had the skill to create his own chances on the deck, rather than relying entirely on service through the centre and via the flanks.