Manchester United Coach Jose Mourinho is convinced his £40 million investment in the acquisition of Nemanja Matic from Chelsea is a wise move.

Mourinho hailed the new signing who recorded a winning debut with the Red Devils on Wednesday. 

The Portuguese gaffer said that Matic is "a genius'' who "thinks football" as the holding midfielder made a bright start with his new club.

Mourinho was however quick in also admitting that the Serbian still lacked full match fitness.

Matic started for the Red Devils in their 2-1 friendly win over Sampdoria and played for 45 minutes.

"He needs time but [his] experience, intelligence, a genius in the way he thinks -- he thinks football.

"We will help him to be ready sooner rather than later", Mourinho said.

Substitute Juan Mata got the winning goal for Manchester United in Wednesday's friendly with 10 minutes left, he coolly side-footed the ball from the edge of the penalty area.