John Ryder claimed the WBO world interim super middleweight title after Zach Parker was forced to pull out at the end of the fourth round with a suspected broken right hand.
Ryder (32-5, 18 KOs), 34, from north London, now hopes he can face Saul "Canelo" Alvarez, the WBO champion, for all four world super middleweight titles in May after overcoming his fellow English fighter Parker in an anticlimactic finish at the O2 Arena in London on Saturday.
"I want the big fights, the Canelo fight," Ryder said afterward.
"It would be a dream to fight Canelo on Cinco de Mayo or be upgraded to full champion."
Alvarez (58-2-2, 39 KOs), 32, is WBO world super middleweight champion, and also holds the other three world titles. The Mexican fighter, one of the biggest stars and cash generators in boxing, plans to compete again in May and Ryder has put himself in the frame to be his next opponent.
If Alvarez decides to face anyone else in May and later step up to light heavyweight to face Dmitry Bivol in a rematch next, after losing on points to the Russian fighter this May, Ryder will dispute the vacant WBO world title in 2023.
Ryder, who lost a controversial decision to Callum Smith for the WBA world title three years ago, edged past New Yorker Daniel Jacobs via a split decision in February and is now seeking a second shot at a full world title.
"I started off the year with a good win and it was important to continue the momentum," Ryder said.
"Zach started well but I felt like the tide was starting to turn and it's a bad injury for him."
Parker (22-1, 16 KOs), 28, went into the fight No 1 in the WBO contender rankings, but was left sickened by the premature end to the fight.
"I hit him with an uppercut at the start of the fourth round and it just went and every time I jabbed him in the fourth round it hurt," Parker said.
Parker, who had last fought a year ago, landed a combination to the body and head in round two and then in the third held his hands low as he flicked out jabs.
The fight was well poised in the fourth round when Parker suffered the injury, which was too painful for him to continue.