Umtiti has developed into one of Europe’s top centre-backs since joining the Spanish giants from Lyon back in 2016.
And his performances under Luis Enrique last season and Ernesto Valverde this year have attracted admiring glances from Mourinho.
The United gaffer is on the lookout for a regular defensive partner for Eric Bailly as the Red Devils plot a summer shake-up of their squad.
And it seems news of Mourinho’s interest in securing Umtiti’s signature has filtered back to his Barcelona team-mate Messi.
According to Diario Gol, Messi knows Mourinho has called Umtiti about swapping the Nou Camp for Old Trafford.
And the Argentine’s face is said to have dropped when he learned of United pursuing the 24-year-old.
Barcelona would be powerless to stop United snatching Umtiti if they meet the £53m (€60m) release clause written into his contract.
And that’s why they are desperately trying to get him to put pen to paper on a new deal, which would vastly increase that clause.
Umtiti is thought to be demanding Barcelona double his £3.5m-a-year (€4m) wages.
He’s apparently willing to jump ship and join United if that request is not acted upon.
Umtiti’s potential exit will come as a blow to Barcelona boss Valverde.
Umtiti is Barca’s most reliable centre-back at present and is a key part of their plans going forward.