 They also beat Sporting Clube de Portugal and Anderlecht to reach the European Cup semi-final, here they came up against cup favourites A.C Milan who proved to be too strong for Dundee, Milan went on to lift the trophy at Wembley Stadium.In 1965 he moved to Watford, where he was the first choice goalkeeper for three years.Early in the 1968–69 season Mike Walker was bought and he replaced Slater as first-choice goalkeeper.