Hann delayed the contest for 15 minutes in the middle of the match to have a tip replaced on his cue after his initial request to make repairs was turned down by referee John Williams.
Glaswegian Dott later described his opponent's attitude as "terrible", adding after a 5-2 second round win: "Quinten is so talented he doesn't need to do these things. I don't like his attitude."
Matters came to a head after Hann's 69 clearance in frame five. He indicated to Williams there was a problem with his tip and requested an adjournment. Williams declined to halt the game and told him work could only be carried out if the tip was coming off. Hann then disappeared and on his return the tip had worked loose.
The match was stopped while assistant tournament director Lawrie Annandale worked on the cue. After the delay Hann won frame six, but Dott took the seventh to earn a last 16 match against John Parrott who beat Leo Fernandez 5-2.
World No 8 Alan McManus beat Willie Thorne 5-3.Reuse content