Fabian Edwards beat Gegard Mousasi by unanimous decision at Bellator 296 in Paris to set up a middleweight title fight against champion Johnny Eblen.
Briton Edwards was the cleaner striker and got the better of many of the grappling exchanges across the five rounds.
Following the bout, he was confronted by American Eblen who was at cage-side.
“One more fight until I get that gold belt and we make history,” said Edwards.
Bellator confirmed Eblen would defend his title against Edwards on 23 September in Dublin.
The victory moves Birmingham’s Edwards, 30, a step closer to MMA history and his dream of joining his brother Leon, who holds the UFC welterweight belt, as a champion.
Siblings like Anthony and Sergio Pettis, and Patricio and Patricky Freire, have all held world titles, but never at the same time across multiple major MMA promotions.
Edwards came into the bout on a two-fight win streak after beating Lyoto Machida and Charlie Ward last year – a run which has seen him rise to second in the Bellator middleweight rankings, one place behind Mousasi.
In Mousasi he was facing a former champion himself, with the Dutch fighter previously holding the middleweight title before losing it to Eblen in June.
Mousasi, 37, was taking part in the 60th bout of a distinguished 20-year MMA career, which has seen him headline bouts across multiple top promotions, including the UFC and Strikeforce.
In the build-up, Edwards described the meeting with Mousasi as the biggest bout of his 13-fight career, which has yielded 11 wins over six years.
With Leon in his corner, Edwards started the fight strongly, landing a sharp straight left on Mousasi while his corner urged him to start using his feet more.
There was controversy in the second round as the fight was stopped following an illegal knee on the ground from Mousasi – a move that infuriated Edwards’ corner, who demanded that the referee deduct a point.
The referee did not punish the former champion, but Edwards did not allow himself to become distracted.
Throughout the next rounds, Edwards mixed up his attacks well, landing a swift right-hand body shot combination on Mousasi, peppering him with leg kicks and landing a takedown.
Mousasi secured a takedown of his own but Edwards quickly got back to his feet, and while he landed sporadic leg kicks on the Briton, he never looked fully comfortable with his striking.
Going into the fifth round, Edwards’ corner told their fighter he had “four rounds in the bank” believing he would secure victory if he survived the final five minutes.
Edwards then stamped his authority on the fight in the closing stages as he took Mousasi down, gained back control and dictated the action on the ground until the final bell.
As the referee brought the fighters together, Edwards mouthed to the camera: “I’m coming – that’s my belt”.
“There are levels. After I suffered my losses. A lot of people wrote me of, thought I was finished,” said Edwards in his post-fight interview.
He then told Eblen “I like that belt”, before the champion responded “that I was a pretty good performance but I’m a much better fighter – that belt is mine”.
Disappointment for France’s Barnaoui
In the co-main event, Brent Primus overcame vociferous support for home favourite Mansour Barnaoui as he ground out a unanimous decision win in their Bellator Lightweight Grand Prix quarter-final.
Barnaoui, 30, was spurred on by the Paris crowd, with some audience members shouting through a megaphone and banging a drum, and a section of the crowd even letting off flares.
In the early stages of the fight, Barnaoui relentlessly pressured American Primus, landing a number of strikes against the cage.
Primus, 38, recovered in the second round to control the fight on the ground, but Barnaoui would come back again in the third, landing a succession of knees from the clinch to a visibly tiring Primus.
Primus looked close to defeat at one stage as he fell to the ground but survived until the fourth round and, remarkably, gained control again in the latter stages of the contest.
A former lightweight champion, Primus out-grappled Barnaoui for the rest of the fight and came close to finishing the bout with a triangle and rear-naked choke before the bell rung.
He will face current champion Usman Nurmagomedov in the semi-finals.
Elsewhere, Edwards’ team-mate Tim Wilde extended his unbeaten streak to five as he beat fellow lightweight Chris Gonzalez by unanimous decision.
There was defeat for Manchester’s Kane Mousah, however, as he suffered a second-round knockout to home favourite Thibault Gouti, while Scotland’s Keir Harvie lost a decision to Fabacary Diatta.
Mousah’s team-mate Saul Rogers‘ bout with Davy Gallon was declared a no-contest after the referee mistakenly stopped the fight early while Gallon was defending a submission hold.