That is the verdict of BT Sport presenter and former England striker Gary Lineker.
Firmino struck in second-half stoppage time to give Liverpool a well-deserved 3-2 win at Anfield.
Salah was not on the pitch at the time and his reaction to the goal while sitting on the substitutes bench went viral on social media.
The Egyptian appeared to throw his water bottle in the background of camera shots showing Reds boss Jurgen Klopp celebrating.
Other footage also showed Salah celebrating with his arms in the air before throwing his bottle.
However, Lineker reckons Salah’s behaviour was because he was relieved for an earlier mistake.
Salah gave the ball away in the lead up to PSG’s equalising goal through Kylian Mbappe.
“He should be relieved because he did give the ball away for Mbappe’s goal, 2-2,” Lineker said.
“He’s annoyed at himself possibly. Yeah relief.”
Manchester United legend Rio Ferdinand was in the studio with Lineker.
And he believed there was nothing untoward with Salah’s reaction.
“I think you have to [look at] the way this team is, the bond they have out there on the pitch,” Ferdinand said.
“I think Salah’s celebrating in his own way. His hands were up at the beginning of that.
“The first picture [shows] his hands were up [celebrating].”
Liverpool‘s victory puts them at the top of Group C.
Red Star Belgrade and Napoli played out a 0-0 draw in the other game in the group.