The Doncaster fighter continued his incredible rise to claim the WBC Silver super bantamweight title at Manchester Arena in the chief support bout to the clash between Scott Quigg and Carl Frampton.
By comfortably and classily outpointing the terrier-like Jorge Sanchez, he also claimed victory in an official world title eliminator for the WBC strap.
Given his incredible improvement and rapid rise from debut little more than five years ago, few will now be quick to rubbish his chances of claiming a world title.
McDonnell dominated Sanchez, a tough Panamanian who came into the contest having stopped 15 opponents in his nine fights.
With a second round knockdown, McDonnell teased a rare stoppage of his own but impressed greatly with a classy show of boxing skill and defensive smarts.
He exploited a considerable height advantage with intelligence and composure, keeping Sanchez at bay with brilliant use of the jab. And he once again showcased his remarkable engine to maintain his level of performance through 12 demanding rounds.
Sanchez marched forward from the off but was far too wild and erratic with his shot choice and landed hardly anything of note in comparison to the number of punches he threw.
McDonnell absorbed plenty on his arms and his gloves and began to weave and duck away from many more. His movement on the night was fantastic and tireless, wearing out Sanchez who had never been beyond eight rounds and blew himself up by the mid-point of the fight.
McDonnell sent Sanchez to the canvas in the second, following up a body shot and left hook with a right hand that landed flush.
Sanchez’s influence was minimal, though he did rock McDonnell in the third but failed to capitalise.
By the time the final bell came, there was no doubt over the outcome. With scorecards of 119-108, 118-110 and 118-109 he claimed a version of WBC’s famous green belt, something which world champion twin brother Jamie does not yet have.
But who would bet against him joining Jamie on top of the world?
The atmosphere was incredible for the much-anticipated world title unification battle between Frampton and Quigg. Frampton took control after a cagey opening, dominating with the jab as Quigg failed to fight back.
The fight exploded into action over the final four rounds when Quigg stepped up his offence and there were plenty of thrilling exchanges. But Frampton had done more than enough to claim victory, even if one judge surprisingly awarded the fight to Quigg, who lost his unbeaten record.
Also on the bill, Doncaster-trained Isaac Lowe claimed the Commonwealth featherweight title when the corner of opponent Marco McCullough threw in the towel in the eighth round.
Lowe, cheered on by world heavyweight champion Tyson Fury, is trained by Dave Hulley and Jimmy Harrington in Lindholme.
Elsewhere, Jason Cunningham produced a comfortable points triumph to win an English bantamweight title for a second time on a stacked Stefy Bull promotion at the Dome in Doncaster.
Woodlands’ former Commonwealth champion beat Ashley Lane 97-93 97-94 and 97-93 across the three cards. He moves to 18-3-1 for his career.
Barnsley’s Matthew ‘Buster’ Mallin survived a points deduction to win a tight contest against Aston Jolly of Doncaster and claim the Central Area middleweight title.
Referee John Latham awarded the Stairfoot fighter a 96-95 decision despite deducting a point in the fifth round for persistent fouling, taking the two-time English title challenger to 10-3-1. Jolly drops to 7-2-1.
Doncaster light heavyweight Daniel Slaney returned to the ring after a four year absence by winning every round against debutant Grzegorsz Semick. Fellow home town fighter lightweight Lewis Booth stretched his 100 per cent record over a third fight with a 40-37 points win over Harvey Helmsley.
And Sheffield welterweight Jayce Dixon won every round against Silvije Kebet on his professional debut.