Cavani agreed a deal to stay for another 12 months, as Sunsport revealed he had been offered a pay hike to £250,000-a-week.
The Sun says the Uruguay forward could earn close to the same again in bonuses if he is in the goals next season.
Cavani, 34, will pick up an extra £100,000 if he is United's leading scorer – and a similar amount if he ends up as the Premier League's Golden Boot winner.
It is also understood that United will promise the South American a rolling annual review, which could even see him staying in England for another season beyond the next one.
Cavani has been a huge hit at United and is already a cult figure to supporters.