The Italian giants booked their place in the Europa League knockout stage, but Mourinho says tougher tasks lie ahead.
AS Roma managed has told his players they need to play better after they booked their spot in the round of 16 of the Europa League following a 3-1 win over Ludogorets on Thursday night.
Roma went into their final group game knowing anything other than a win would see them drop to the Europa Conference League.
The Italian side started poorly as Ludogorets went into the break with a one-goal lead, courtesy of a superb strike from Rick in the 41st minute.
However, Roma came back in the second half as two Lorenzo Pellegrini penalties and Nicolo Zaniolo's solo strike secured a 3-1 win for the Italian side.
But while the result looked comfortable on paper, it was far from perfect for Roma as Ludogorets had a goal ruled out following a VAR review.
And with Champions League teams waiting in the second round, Mourinho has urged his players they would need to play better than they did in the group stages.
"It was a really difficult game, Mourinho said after the game. Ludogorets know how to play, they have people with creativity, pace, who can do what they did in Bulgaria when we lost and today on the first goal."
"In the second half, we came on with a different attitude and intensity. Nicolò and Cris obviously gave us something different, as it's not the same to face strikers like Tammy and Belotti.
"We turned it around, but we have got to play better, we are now up against the sharks who come down from the Champions League and need to do better all around than this," Mourinho added.
Roma will find out their opponents for the round of 16 when the draw is made on Monday, November 7. However, before then, Jose Mourinho's men have a big derby coming up this Sunday against Lazio.