Walker left Chelsea at the end of the 1983–84 season following a contract dispute, and signed for Sunderland. He returned to haunt his old side the following season in the League Cup, when the teams were drawn together in the semi-finals. In the second leg at Stamford Bridge, Walker inspired Sunderland to a 3–2 win, giving them a 5–2 aggregate lead, which provoked a near-riot; at one point a Chelsea fan entered the pitch and chased Walker. In the final at Wembley, however, Sunderland lost 1–0 to Norwich City, with Walker missing a penalty when he hit his shot against the post.