The Finnish side were reduced to 10 men after just 15 minutes when Miro Tenho was sent off but Roma didn’t open the scoring until after half time through Paulo Dybala.
Lorenzo Pellegrini then doubled Roma’s lead shortly after before Belotti scored his first goal for the club since his arrival from Torino on a free transfer in the summer.
Belotti, who scored 100 goals in Serie A during his seven seasons with Torino, has found it difficult to make an impact during his first few appearances for Roma.
And Mourinho believes the 28-year-old is trying too hard to score the perfect goal.
‘We need to improve in building from the back. We have this difficulty, I try to hide it,’ Mourinho said after Roma’s win over HJK Helsinki.
‘We have super-talented players up front, but we have to play meaner. We have to be mean when it comes to the attack.
‘You must be mean and nasty if you want to put the ball into the back of the net.
‘Belotti also seems to be suffering from this disease we have up front, today I saw him do four or five heel touches. This is not him.
‘He has to score, with his knee, with his ass, with his head. He has the virus of a playmaking wizard, whereas he just needs to score. That’s it.
‘We need to improve in terms of execution, the average of shots and goals made is not good.’
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