The Doncaster hero, 24, who won British, Commonwealth and European titles last year, had to show a champion’s resolve to cling onto his title against the aggressive Stephane Jamoye.
The Belgian Jamoye came to upset the odds as well as the raucous crowd at the Doncaster Dome, and the shock looked on when he caught McDonnell flush in the second round with a counter right.
McDonnell was sent reeling from the punch and had to tie up Jamoye to survive the round.
The younger Jamoye, 21, has won away from home before and he proved that he was going to be no pushover by throwing the majority of the shots in the opening round.
Encouraged to step it up in the second half of the fight by trainers Stefy Bull and Dave Hulley, McDonnell did so and used his height and reach to his advantage to keep a tiring Jamoye at bay.
Roared on by the crowd, McDonnell started to take the initiative and punished Jamoye with body shots in the seventh.
Aside from showing his aggression, speed and confidence, Jamoye also displayed his courage throughout and he was never going to be stopped by the improving McDonnell.
A point deduction in the tenth for consistent pushing from McDonnell could have threatened the overall result but he had done enough to win a majority decision verdict.
Finnish judge Esa Lehtosaari scored it 115-113 and German Jurgen Landos 114-113 both in the favour of McDonnell, whilst Frenchman Christophe Fernandez scored it level at 114-114.
A dazed and emotional McDonnell told The Star: “For some reason I thought it was in about round eight when he caught me, but it was actually round two!
“Honestly I went out in the first round and when I came back it was suddenly the 11th. I wanted to enjoy the atmosphere but I feel like I went out there, did it and didn’t even notice anything.
“It wasn’t the best performance that I’ve got in me and I’m disappointed about that. But I can learn from this. He was a tough kid and he did hurt me a little bit.”
The partisan home crowd were momentarily silenced when McDonnell was caught and Bull admitted that he panicked when it happened.
He said: “There’s no doubt we were worried in the second. It’s my job as a trainer to be worried when things like that happen. But the heart he showed to come back proved it was a world-class performance and I’m so proud to be a part of this camp.
“The idea is you’re going up different levels all the time and that kid was a world-class fighter and it took a world-class performance to beat him.”
Also on the card was the precocious Sheffield middleweight Liam Cameron and he recorded his eighth straight victory with a stoppage win over Lester Walsh.
Cameron was always in control of the fight but took his time to figure out Walsh’s weaknesses before unleashing a devastating finish in the fourth.
Patient but always ready to pounce, Cameron sent Welsh onto the ropes with an uppercut and then unleashed a flurry of shots that forced the referee to step in.
Doncaster’s Maxi Hughes made it three wins from three with a shutout 40-36 win over York’s Graham Fearn.
Hughes’ stablemate Chad Gaynor notched his fifth win with the same score against Kristian Laight in his one hundreth contest.
Jamie’s twin brother, Gavin’s fight with Chuck Jones was called off after the Welshman showed up over the featherweight weight limit.