Former England cricket captain Andrew Flintoff climbed off the canvas to win a points decision over American Richard Dawson on his heavyweight boxing debut.
The 34-year-old, who retired from cricket in September 2010, was floored by a short left early in the second.
Flintoff was the busier fighter in four scrappy two-minute rounds though and ended 39-38 ahead on the scorecard.
"You talk about the Ashes and things but as a personal achievement, this is the best," Flintoff told BoxNation.
Flintoff admitted that his first fight may also be his last however, adding: "We'll see how we go. It's not natural to me, I've had to work so hard.
"The feeling of being in there and winning at the end, I can't believe it but I'm not pretending to be something I'm not."
IBF super-middleweight champion Carl Froch said: "Any attention for boxing is good to a degree. Flintoff did himself proud. He threw a lot of punches. If anything, he was too eager.
"He got in there and had a swing-up and didn't get hurt. Fair play to him.
"If he wants to win a regional title or a British title, it would be a few years away but it's not unfeasible."
BBC Sport's Olly Foster witnessed the fight at the Manchester Arena: "Flintoff always said he'd go about it the right way and he proved a lot of people wrong.
"Reputations were on the line, not least the McGuigan family in his corner and also the British Boxing Board of Control, whose general secretary Robert Smith had been criticised for giving a 34-year-old a licence."
Ex-Lancashire all-rounder Flintoff was a key part of the England side that ended an 18-year wait for an Ashes victory with a 2-1 triumph in the 2005 series against Australia.
His last first-class appearance was at the Oval in Australia's return four years later as England regained the urn. He left the Test arena with an average of 32.78 runs and 226 wickets at a rate of 31.77.