Having scored twice in the encounter, the Egypt international helped his strike partner complete his first hat-trick of the season by allowing the 27-year-old take the second penalty they were awarded in the game.
“No, I wasn’t surprised,” Firmino told Liverpool’s official magazine.
“I was really happy with his unselfish act of giving me the ball and once again I thank him for it.”
Firmino has scored 11 goals this season while his strike partner Salah has 19 goals to his name in all competitions including his 16 in the Premier League to rank him as the topscorer thus far.
Liverpool play host to Leicester City in their next league game on January 30 at Anfied.