The Uruguay international wasn’t in Ole Gunnar Solskjaer’s plans during this window, but is seen as an opportunity United couldn’t turn down.
The Norwegian believes the addition of Cavani, alongside Anthony Martial, Marcus Rashford and Mason Greenwood will form one of the deadliest attacks in world football.
His arrival now also means United will not be left trying to secure a replacement for Odion Ighalo when the Nigeria striker’s loan deal expires in January.
Cavani held talks with Solskjaer on Saturday, when the United manager was convinced the 33-year-old had ‘unfinished business’ and would add world-class quality to his squad.
Despite the move for the former Paris Saint-Germain veteran, within Old Trafford they insist the transfer strategy has not altered, with the club focusing on a mix of homegrown talent and high-quality recruits.
United are also close to completing a deal for Alex Telles from Porto and still hope to bring in a right winger before the window closes on Monday.