Greenwood did not select Mariner for England throughout 1979, although Mariner had his most productive spell for Ipswich that season, scoring 13 goals in 33 matches. It was not until 1980 that he won a sixth England cap – almost exactly two years after his fifth – and he scored England's goal in a surprising 4–1 defeat against Wales at Wrexham. He stayed in the reckoning thereafter, scoring in a 2–1 win over Australia in Sydney in the final game before England took to the field for the 1980 European Championships. Mariner was named in Greenwood's squad for the tournament, despite not playing during the whole qualifying campaign.