With 14 of his own league strikes, meanwhile, and 23 overall this campaign, Firmino has already surpassed his previous season-best in both the Premier League and in all competitions, beating the marks set in 2016-17 for the Reds (11 Premier League goals) and back in 2013-14 with Hoffenheim (22) respectively. The record was previously held by Spaniard Fernando Torres, who mustered 33 during the 2007/08 season.
The former skipper said on BT Sport: "It's hard to find new words. But his performance this season in a debut season has been magnificent".
Liverpool forward Mohamed Salah is on his way to reaching the elite level of Lionel Messi but has no interest in being compared to the prodigious Barcelona striker, manager Juergen Klopp has said.
Spurs thrash Swans to book semi-final date
But the victory was not without controversy as, with Spurs 1-0 ahead, Heung-Min Son's 23rd-minute goal was ruled out for offside. But Tottenham were unruffled and quickly settled into a tempo that had the home side outnumbered and second best in midfield.
"Yes, I think Mo is on the way", he said.
"He gave us a good four goals". Also I think you've got to go out to him quicker, don't let him build up a pace to turn you inside out at that pace. It could have been really hard tonight. It was slippery. Everybody suffered but not Mo in that situation.
Salah is now comfortably the leading goalscorer in Europe's top five leagues, surpassing Kane, Lazio's Ciro Immobile, PSG's Edinson Cavani and Barcelona's Lionel Messi, who are all on 24.
A sudden change of direction in the penalty box took him clear of two defenders, including Miguel Britos who tied himself into a knot as he crashed to the ground, before Salah beat goalkeeper Orestis Karnezis at the near post.
Premier League defenders are finding it impossible to stop the 25-year-old, but former Premier League defender Campbell thinks he has the answer.