The striker, who bagged the Reds' second goal, left the pitch after Spurs centre-back Vertonghen poked him in the eye.
Liverpool manager Jurgen Klopp provided an update on the Brazil international's condition after the game, per Chris Shaw of the club's official website:
"I'm not sure, but there may be an injury with Roberto, we don't know exactly in the moment. It's something with his eye, we will see. I didn't see it back. I only saw the situation from around 60 yards. I have no clue what exactly happened. But it's something with the eye and for sure in the moment it's not comfortable for him. We will see."
Images of the incident show exactly what happened:
Even so, Vertonghen somehow escaped punishment:
Being without Firmino would be a blow for Klopp, particularly with a UEFA Champions League game against Ligue 1 giants Paris Saint-Germain on Tuesday. Fortunately, Klopp has several intriguing options for replacing Firmino.
He could put former Chelsea youngster Dominic Solanke through the middle, giving the 21-year-old an chance to prove he can lead the line in England's top flight.
Alternatively, Klopp could give the nod to oft-injured Daniel Sturridge. When fit, Sturridge is a ruthless finisher who would help keep the Reds among the goals.
Sturridge's lengthy injury history and Solanke not starting a game this season could encourage Klopp to put Xherdan Shaqiri on the wing and deploy star man Mohamed Salah centrally.
Firmino's intelligent movement and flair will be missed if he's out, but Liverpool have the attacking resources to cope.