The Frenchman's future is bound to be a big talking point this summer, with his current deal set to expire in June 2022.
Ighalo spent a year playing alongside Pogba before leaving Old Trafford in January, and believes the club should keep the World Cup winner.
"Apart from playing on the pitch, he's a good guy in the dressing room, a funny guy, he's always happy.
"The only time he isn't happy is when he's not playing and I can understand that - everyone wants to play.
"If Manchester United have the opportunity to keep him on a new, longer deal, they should because he is so influential.
"Sometimes he doesn't have the best of games but that's normal, you can't be 100% in every game but when he turns up, like he did yesterday against Tottenham, he is exceptional."