The 25-year-old from Telford achieved the game's perfect run during the fourth frame of a 5-4 victory over the Netherlands' Mario Wehrmann, which also stretched his unbeaten sequence to 13 matches.
Currently ranked 197th in the world, Gunnell will now collect a pounds 5,000 maximum break bonus - more than his entire tournament earnings combined during the first four years of an otherwise undistinguished professional career.
"It wasn't until I potted the 14th red that I began to think seriously about a 147," Gunnell said, who had compiled 15 maximum breaks in practice but never before under tournament conditions. "I cut that red into a baulk pocket, knocked in a really difficult black and from then on it was pretty straightforward. Mind you, when I got down to the last few colours I started to feel really nervous."
Gunnell, a former England amateur international, was so exhausted after the 147 that he fell 3-2 behind and was relieved to scrape through the match in the deciding frame.
"When you are involved in a lot of close finishes like I have been recently the tension drains you, but this is a real boost and something I'll not forget in a hurry," he added.
Gunnell returns to action today with a second-round engagement in the Thailand Masters against Llanelli's Phil Williams.Reuse content