Kenny Shiels the League Cup Final, where they upset the odds by beating Celtic 1–0, with Dieter van Tornhout scoring the crucial goal in the 83rd minute. Killie's joy was tempered by the death of Liam Kelly's father, Jack, who suffered a fatal heart attack at the final whistle of the game. On the win, Shiels stated the team "are thinking more about Liam (Kelly) than our triumphalism". He then told BBC Scotland's Jonathan Sutherland, winning the cup is "unbelievable", in addition "a great emotion" for the Kilmarnock's supporters. Following his side's historic cup win, Shiels announced his intention to stay at
Dean Shiels cost-cutting that is due to take place at the club; manager Ally McCoist refuted this. On 8 February 2014, Shiels scored a hat-trick in the Scottish Cup, as Rangers won 4–0 against Dunfermline Athletic. On 10 June 2016, Shiels left Rangers after his contract came to an end. He had made 43 appearances for Rangers in his final season with the club, as they won promotion to the Scottish Premiership. On 25 August 2016, Shiels signed for Dundalk in the League of Ireland Premier Division citing the "lure of European football" as one of the things that attracted him to