Jurgen Klopp claimed Mohamed Salah would not like the comparison - but the Liverpool manager agrees the Egyptian has similarities to Lionel Messi.
Salah also created another goal for Roberto Firmino in a devastating display amid snow flurries and freezing conditions at Anfield.
Harry Kane, ruled out by injury, is second in the odds at 8/1.
Asked in his post-match press conference if Salah could be mentioned in the same sentence as five-time world player of the year Messi, Reds boss Klopp said: "I think Mo is on the way.
"I don't think Mo or anybody else wants to be compared with Lionel Messi - he is the one who has been doing what he's been doing for what feels like 20 years or so. The last player I know who had the same influence on a team performance was Diego Maradona.
"But Mo is in a fantastic way, that's for sure. As it always is in life, if you have to have the skills you have to show that constantly and consistently, and he is very good. He helps us a lot.
"The boys love playing together with him, he loves playing with them so it's good.
"He gave us a good four goals. I think that's quite exceptional and another good performance.
"We had to cope and deal with difficult conditions tonight. It was slippery. Everybody suffered but not Mo in that situation. That is really special."
Watford offered little aside from a dipping free-kick from Roberto Pereyra when they were already 3-0 down. The result never seemed in doubt after Salah opened the scoring in the fourth minute.
Klopp said: "I'm really happy about the result and the performance in very difficult circumstances."
