| Jason Curtis defeated Mark O'Sullivan |
1997 World Championship Snooker |
| John Whitty defeated Mark O'Sullivan |
1996 UK Championship Snooker |
| John Read defeated Mark O'Sullivan |
1996 Grand Prix Snooker |
| Mark O'Sullivan defeated Simon Smith |
1996 Grand Prix Snooker |
| Paul Sweeny defeated Mark O'Sullivan |
1996 World Championship Snooker |
| Peter Lines defeated Mark O'Sullivan |
1996 British Open Snooker |
| Mark O'Sullivan defeated Roy Bigg |
1996 British Open Snooker |
| Steve Archer defeated Mark O'Sullivan |
1996 Thailand Open Snooker |
| Joe Jogia defeated Mark O'Sullivan |
1996 European Open Snooker |
| Mark Tucker defeated Mark O'Sullivan |
1998 UK Tour - Event 1 Snooker |
| Karl Broughton defeated Mark O'Sullivan |
1996 International Open Snooker |
| Mark O'Sullivan defeated Damian Massey |
1996 International Open Snooker |
| Gary Ponting defeated Mark O'Sullivan |
1996 Welsh Open Snooker |
| Mark O'Sullivan defeated Adrian Gunnell |
1996 Welsh Open Snooker |
| Peter Lines defeated Mark O'Sullivan |
1995 German Open Snooker |
| Mark O'Sullivan defeated Andy Duff |
1995 German Open Snooker |
| Robin Hull defeated Mark O'Sullivan |
1995 UK Championship Snooker |
| Mark O'Sullivan defeated John Dunning |
1995 UK Championship Snooker |
| Lee Richardson defeated Mark O'Sullivan |
1995 Grand Prix Snooker |
| Mark O'Sullivan defeated Joe Grech |
1995 Grand Prix Snooker |
| Mark O'Sullivan defeated Gary Peters |
1995 Grand Prix Snooker |
| Peter Daubney defeated Mark O'Sullivan |
1995 Thailand Classic Snooker |
| Mark O'Sullivan defeated Colm Gilcreest |
1995 Thailand Classic Snooker |
| Steve Archer defeated Mark O'Sullivan |
1995 World Championship Snooker |
| David Singh defeated Mark O'Sullivan |
1995 British Open Snooker |
| Fergal O'Brien defeated Mark O'Sullivan |
1995 Thailand Open Snooker |
| Mark O'Sullivan defeated Steve Harrison |
1995 Thailand Open Snooker |
| Mark O'Sullivan defeated Craig Edwards |
1995 Thailand Open Snooker |
| Mark O'Sullivan defeated Glenn Stevenson |
1995 Thailand Open Snooker |
| Mark O'Sullivan defeated David Thompson |
1995 Thailand Open Snooker |
| Darren Lennox defeated Mark O'Sullivan |
1995 International Open Snooker |
| Mark O'Sullivan defeated Mark Williams (II) |
1995 International Open Snooker |
| Nick Pearce defeated Mark O'Sullivan |
1995 Welsh Open Snooker |
| Mark O'Sullivan defeated Alistair Fleming |
1995 Welsh Open Snooker |
| Graeme Dott defeated Mark O'Sullivan |
1994 European Open Snooker |
| Jim Chambers defeated Mark O'Sullivan |
1994 UK Championship Snooker |
| Mark O'Sullivan defeated Edvard Matthiasson |
1994 UK Championship Snooker |
| Mark O'Sullivan defeated Andrew Alexandrou |
1994 UK Championship Snooker |
| Matt Wilson defeated Mark O'Sullivan |
1994 Grand Prix Snooker |
| Mark O'Sullivan defeated Andrew Alexandrou |
1994 Grand Prix Snooker |
| Kevin Smith defeated Mark O'Sullivan |
1994 Dubai Classic Snooker |
| Fergal O'Brien defeated Mark O'Sullivan |
1994 World Championship Snooker |
| Mark O'Sullivan defeated Cliff Wilson |
1994 World Championship Snooker |
| Mark O'Sullivan defeated Oliver King |
1994 World Championship Snooker |
| Mark O'Sullivan defeated Shokat Ali |
1994 World Championship Snooker |
| Mark O'Sullivan defeated Matt Gibson |
1994 World Championship Snooker |
| Mark O'Sullivan defeated Jamie Bodle |
1994 World Championship Snooker |
| Mark O'Sullivan defeated David Thompson |
1994 World Championship Snooker |
| Ian Brumby defeated Mark O'Sullivan |
1994 British Open Snooker |
| Mark O'Sullivan defeated Mario Morra |
1994 British Open Snooker |
| Mark O'Sullivan defeated Nick Pearce |
1994 British Open Snooker |
| Mark O'Sullivan defeated Richard McHugh |
1994 British Open Snooker |
| Ryan Milton defeated Mark O'Sullivan |
1994 Thailand Open Snooker |
| Stephen Lee defeated Mark O'Sullivan |
1994 International Open Snooker |
| Mark O'Sullivan defeated Nick Fruin |
1994 International Open Snooker |
| Mark O'Sullivan defeated Jack Fitzmaurice |
1994 International Open Snooker |
| Mark O'Sullivan defeated Hitesh Lakhani |
1994 International Open Snooker |
| Joe Grech defeated Mark O'Sullivan |
1994 Welsh Open Snooker |
| Mark O'Sullivan defeated Colin Roscoe |
1994 Welsh Open Snooker |
| Mark O'Sullivan defeated Kevin Ashby |
1994 Welsh Open Snooker |
| Mark O'Sullivan defeated Nic Barrow |
1994 Welsh Open Snooker |
| Mark O'Sullivan defeated Philip Williams |
1994 Welsh Open Snooker |
| Tony Drago defeated Mark O'Sullivan |
1994 Strachan Challenge - Event 1 Snooker |
| Stefan Mazrocis defeated Mark O'Sullivan |
1994 Strachan Challenge - Event 2 Snooker |
| Jamie Burnett defeated Mark O'Sullivan |
1993 European Open Snooker |
| Mark O'Sullivan defeated Alan Edmonds |
1993 European Open Snooker |
| Jimmy Long defeated Mark O'Sullivan |
1993 UK Championship Snooker |
| Mark O'Sullivan defeated Stuart Henderson |
1993 UK Championship Snooker |
| Sergio Beggiato defeated Mark O'Sullivan |
1993 Grand Prix Snooker |
| Mark O'Sullivan defeated Andrew Prydden |
1993 Grand Prix Snooker |
| Mark Evans defeated Mark O'Sullivan |
1993 Dubai Classic Snooker |
| Mark O'Sullivan defeated Jayson Morris |
1993 Dubai Classic Snooker |
| Steve Duggan defeated Mark O'Sullivan |
1993 World Championship Snooker |
| Mark O'Sullivan defeated Roger Bales |
1993 World Championship Snooker |
| Mark O'Sullivan defeated Pat Houlihan |
1993 World Championship Snooker |
| Mark O'Sullivan defeated Paul Wykes |
1993 World Championship Snooker |
| Mark O'Sullivan defeated David Lazenby |
1993 World Championship Snooker |
| Mark O'Sullivan defeated Andrew Clark |
1993 World Championship Snooker |
| Mark O'Sullivan defeated Mike Russell |
1993 World Championship Snooker |
| Alex Borg defeated Mark O'Sullivan |
1993 International Open Snooker |
| Mark O'Sullivan defeated John Clouden |
1993 International Open Snooker |
| Mark O'Sullivan defeated Kevin Brown |
1993 International Open Snooker |
| Mark O'Sullivan defeated Suriya Suwannasingh |
1993 International Open Snooker |
| Kevin Young defeated Mark O'Sullivan |
1993 Asian Open Snooker |
| Mark O'Sullivan defeated Michael Huntingdon |
1993 Asian Open Snooker |
| Mark O'Sullivan defeated Jason Curtis |
1993 Asian Open Snooker |
| Mark O'Sullivan defeated Paul Smith (II) |
1993 Asian Open Snooker |
| Chris Milner defeated Mark O'Sullivan |
1993 Welsh Open Snooker |
| Mark O'Sullivan defeated Jason Greaves |
1993 Welsh Open Snooker |
| Craig Harrison defeated Mark O'Sullivan |
1992 UK Championship Snooker |
| Graham Cripsey defeated Mark O'Sullivan |
1993 Strachan Challenge - Event 3 Snooker |
| Mark O'Sullivan defeated Hassan Vaizie |
1993 Strachan Challenge - Event 3 Snooker |
| Mark O'Sullivan defeated Andrea Barbacane |
1993 Strachan Challenge - Event 3 Snooker |
| John Rees defeated Mark O'Sullivan |
1993 Strachan Challenge - Event 2 Snooker |
| Oliver King defeated Mark O'Sullivan |
1992 Strachan Challenge - Event 1 Snooker |
| Mark O'Sullivan defeated Karl Burrows |
1992 Strachan Challenge - Event 1 Snooker |
| Mark O'Sullivan defeated Andrew Alexandrou |
1992 Strachan Challenge - Event 1 Snooker |
| Gary Bampton defeated Mark O'Sullivan |
1992 Grand Prix Snooker |
| Michael Gold defeated Mark O'Sullivan |
1992 Dubai Classic Snooker |
| Mark O'Sullivan defeated Mark Darnes |
1992 Dubai Classic Snooker |
| Mark O'Sullivan defeated Alexander Ferguson |
1992 Dubai Classic Snooker |
| Mark Williams defeated Mark O'Sullivan |
1991 World Masters - Juniors Singles Snooker |
| Mark O'Sullivan defeated Darren Shaw |
1991 World Masters - Juniors Singles Snooker |
| Mark O'Sullivan defeated Gary Erwin |
1991 World Masters - Juniors Singles Snooker |
| Dylan Leary defeated Mark O'Sullivan |
1993 Irish Professional Championship Snooker |
| Mark O'Sullivan defeated Declan Hughes |
1993 Irish Professional Championship Snooker |