The former SIMTA British super-middleweight Thai boxing champion only made the switch to conventional boxing last October in a bid to keep fit.
But his second round knock-out of Graeme Bell from Shotton Boxing Club at Warrington's Parr Hall last week has convinced him he can earn national honours in the sport.
He said: "I joined Bridgefoot Boxing Club in Warrington last October to keep in shape.
"But after a few sparring sessions Derek Groark, the coach, told me I had what it took."
His showing last week didn't do anything to deter Groark from that opinion and now Brett has his heart set on national glory in a different sport.
"I'm hoping to compete in the national amateur championships next year," he added.
Despite being a novice in comparison to Bell, who has a host of fights under his belt, Mankee won Thursday's confrontation convincingly.
Bell was knocked down for a compulsory eight count in the opening round of the scheduled three-round contest.
The referee then stopped the fight in the second round when it was clear Bell couldn't cope with the barrage of punches coming his way.
For Mankee, who is 30 and from Hartford, the bout was the end to a frustrating time. Three previous fights had been cancelled over the Christmas period.
Now he hopes to continue his winning run with two bouts in quick succession. On Saturday he is due to fight in the Isle of Man before returning to Warrington for another clash the following week.
Of the transition from Thai boxing Brett said: "It was quite simple to pick up but I must admit that my first reaction when he punched me was to kick him in the chest. Fortunately, I managed to control myself."
Converted for the new archive on 13 March 2001. Some images and formatting may have been lost in the conversion.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article