Martial scored in both of the games he has started since coming back from a thigh injury - against Partizan Belgrade in the Europa League and at Norwich City last weekend - as United bounce back from a miserable start to the season by going unbeaten in four matches in all competitions.
"Anthony looks happier. He seems happy. He is an infectious boy. You can see he is happy here and that rubs off on everyone and it's great to see," United boss Solskjaer told reporters.
"The mood with the whole group, it's miles better on the training ground. The players encourage each other, so it's nice to be a manager when you see them come out and wanting to do extras, so we are improving".
Martial's form and mood is just what Solskjaer needs for the season and giving him extra responsibility for the team's goal-scoring.