During the 1978–79 season, O'Neill was an unused substitute in Widnes' 16-4 victory over Warrington in the 1978–79 John Player Trophy Final at Knowsley Road, St Helens on Saturday 28 April 1979.
He played as a substitute in Widnes' 12-3 victory over Wakefield Trinity in the 1978–79 Challenge Cup Final at Wembley Stadium, London on Saturday 5 May 1979, in front of a crowd of 94,218.
During the 1983–84 season, O'Neill played at prop in the 10–18 defeat by Leeds in the 1983–84 John Player Special Trophy Final during the 1983–84 season at Central Park, Wigan on Saturday 14 January 1984, and he played at second-row in the 19-6 victory over Wigan in the 1983–84 Challenge Cup Final at Wembley Stadium, London on Saturday 5 May 1984, in front of a crowd of 80,116.
O'Neill played in Widnes' 20-14 victory over Wigan in the Charity Shield during the 1988–89 season at Okells Bowl, Douglas, Isle of Man on Sunday 21 August 1988, and played at second-row in the 6–12 defeat by Wigan in the 1988–89 John Player Special Trophy Final during the 1988–89 season at Burnden Park, Bolton on Saturday 7 January 1989.
[5] He was a substitute in Leeds' 16-26 defeat by Wigan in the 1993–94 Challenge Cup Final during the 1993–94 season at Wembley Stadium, London on Saturday 30 April 1994, in front of a crowd of 78,348.