Substitute Marouane Fellaini headed United into a deserved first-half lead and compatriot Romelu Lukaku followed suit early in the second period with his first goal in the Champions League group stage.
"I don't know (what the severity is)", Mourinho told MUTV, the club's in-house television station.
"I feel pretty confident and know what I'm able to do".
While Mourinho was still unsure about the extent of the France international's injury, the Portuguese tactician said Pogba could be missing for a few weeks.
"It looks for me too (like a hamstring injury) but I haven't spoken yet to the medical department".
But while Fellaini will be included in the squad if fit, Phil Jones and Eric Bailly both definitely miss out as a result of UEFA suspension.
Pogba has enjoyed a fine start to the season, scoring twice in United's opening two Premier League games.
Jose Mourinho has urged Zlatan Ibrahimovic to take his time with his rehabilitation from a serious knee injury following the Swede's one-year contract renewal with Manchester United.
"We want him, but we want him in his best condition". "It's hard when you're in and out of the team but we have to find the positives out of it and I think we have both done that", the England global said.