The Red Devils triggered their one-year extension option earlier this week, as predicted, to ensure the veteran midfielder would not be able to quit Old Trafford for free this summer.
Matic was heading for the exit door until midfielder Scott McTominay got injured over the Christmas period, giving boss Ole Gunnar Solskjaer little option but to bring the 31-year-old back in from the cold.
The former Chelsea enforcer had only started two Premier League games before the festive period, with Italian giants Inter Milan speaking to his representatives about a possible switch to the San Siro.
Matic, however, has been pivotal in United remaining unbeaten in their last 10 games, claiming big wins against Manchester City, Chelsea and Wolverhampton Wanderers.