Firmino starred in Liverpool’s 3-0 win over Burnley at Turf Moor on Saturday as he scored one of the three goals scored by the side, becoming the first Brazilian to score 50 Premier League goals.
After four Premier League games thus far, the 27-year-old has recorded two goals and two assists and Robertson believes the club would have been lost with the absence of his team-mate Firmino.
"With his work-rate, his technique, his goals and his all-round play, I don't think there's anyone like him," he told UK media.
"People will say there are better strikers, but for me what he does is so important to our team. We'd be lost without him. He's world-class."
Firmino set up Sadio Mane before climaxing Liverpool's win with a goal with 10 minutes remaining.
And stressing on the defensive qualities of the versatile forward, Robertson said Firmino’s ability to drawback is always important for Liverpool.
"He does everything, and that's the beauty of Bobby. He can do it all. He's our first line of defence, and I've not seen anybody better at doing that," he said.
"He presses the defenders and doesn't give them a minute. He comes back and nicks the ball in midfield for us.
"He's so important defensively for us, then he goes up the park and scores goals and makes assists. That's what we need him to do."
Liverpool currently top the Premier League table with twelve points, two points above title rivals Manchester City.
