Look at his 2nd goal again - it really is a joy to watch.
From the moment he flicks the ball to Milner he is immediately off running into space. As their defence focuses on Milner and Lallana, he runs on the blind side of 2 players and makes a dash for the box, all the time watching Lallana to anticipate the cross. He still has so much to do, and as good as Lallana's cross is (an absolute peach of a ball when running at pace and under pressure), Firmino takes the pace off it beautifully and waits until just the right moment when the keeper commits himself and then simply guides it the other way over his shoulder.
I don't want to compare him to Suarez (as he isn't Suarez), but his running, energy and willingness to always create danger is exactly what we need at the moment and long may his form continue.