In his first season on the main tour, he reached the last 16 at the 1990 European Open, where he defeated Ian Williamson, Steve Longworth, Dennis Taylor and Martin Clark and was drawn against the resurgent Colin Roscoe.

In the 2000 Malta Grand Prix, Dyson beat Craig MacGillivray, Neal Foulds, John Read and Dave Harold to reach the last 32, but was selected to play in the wildcard round; drawn against Joe Grech, he made breaks of 96, 112, 107 and 108 but lost 4–5.

[1] Dyson qualified for the 2001 World Championship, making his first appearance at the Crucible in ten years, by beating Ian Brumby, Mark Gray, Steve James, Rod Lawler and Brian Morgan.

Earlier in the 2000/2001 season, he had compiled his second 147 maximum break in professional competition, against Robert Milkins in the UK Championship.

[2] Following a 6–10 loss to Matthew Couch in qualifying for the 2006 World Championship, Dyson finished the 2005/2006 season ranked 87th; as only the top 64 automatically retained their places, he was relegated from the tour in the summer of 2006.