Sarr broke the deadlock when he tapped home Abdoulaye Doucoure’s low cross nine minutes after the break.
The Senegalese doubled Nigel Pearson’s men advantage six minutes later after receiving the final pass from Deeney.
The icing on the cake came on the 72nd minute mark when Sarr returned the favour by setting up Deeney for the Hornets’ third goal.
After ending Liverpool’s 44-game unbeaten league run, Watford’s captain was quick to acknowledge the impact of Sarr, but admits the 22-year-old has a lot to learn.
"Ismaila Sarr is an unbelievable player, unbelievable talent. He still has a lot to learn, and will continue to learn,” the Englishman told reporters.
Deeney also lauded goalkeeper Ben Foster, who has been one of Watford’s best performers this season.
He added: "It's about time Ben Foster has a week off! He's been keeping us in it for a lot of games this season. He's getting better like a fine wine.”
"We have to take it for what it is, it's three points and we go again. This one we'll enjoy for a day or two, then back on the pitch to get ready for a tough game against Crystal Palace.”
"I'm not looking at anybody else, I'm looking at what we're doing. All we can do is control our own destiny and thankfully we're in a position to do that.”
“We knew we had to try and get a result. This is massive for us."
Watford have now moved out of the relegation zone thanks to a first league win since January 12.
