Miguel Britos denied Liverpool of an emphatic comeback at Vicarage Road as Mohamed Salah looked to have claimed all three points for the visitors.
The Reds went behind early due to poor defending from the set play and Stefano Okaka obliged. Once Sadio Mane had gained parity, Abdoulaye Doucoure then netted a scrappy goal to take the lead once more.
Liverpool came out fighting in the second half and Roberto Firmino converted from the spot before he found Salah exquisitely for what looked like the winner.
But slack play from the set-piece once more allowed Britos to bundle in a priceless goal to earn a draw.