Eleider Alvarez knocked out Michael Seals with a single powerful right hand on Saturday night in New York.
The 35-year-old returned to the ring for the first time in 11 months, having not fought since losing his WBO light-heavyweight world title in a rematch with Sergey Kovalev last February.
Alvarez remains highly ranked with the WBO and will have now boosted his position by KOing Seals.
This could prove important for the next stage of his career as Kovalev subsequently lost the belt to Canelo, who has now vacated it to move back down in weight.
The WBO are yet to reveal who they will order to compete for the vacant crown.
In last month’s rankings, Alvarez was at #7 but this may now change and he could move into a position to fight for the title.
If not, ‘Storm’ will still be well placed to earn a mandatory position and challenge the new champion regardless.