Watford moved out of the relegation zone as their stunning revival under new manager Nigel Pearson continued with a 3-0 victory at south coast strugglers Bournemouth on Sunday.
French midfielder Doucoure opened the scoring just before half time before Ismaila Sarr pounced on a poor clearance by Bournemouth goalkeeper Mark Travers to centre for his captain Deeney to hammer home from close range on 65 minutes.
Bournemouth offered little by way of a response and substitute Roberto Pereyra completed the rout in stoppage time.
The win, Watford's fourth in the six games since Pearson took charge with them bottom of the table, lifted them to 17th place, ahead of Aston Villa who play Manchester City later.
Pearson, who inspired Leicester City's escape from relegation in 2014/15, has collected 13 points from his six matches at the helm, five more than his predecessors Javi Gracia and Quique Sanchez Flores, both sacked this season, managed between them.
"He has stripped it back to basics," Watford captain Deeney said. "I don't want to be too simplistic because that doesn't do him enough credit. He puts demands on the players and the players have accepted those demands."
While Watford, who won only one of their opening 17 league games, are on the up, Bournemouth's hopes of a sixth successive season of top-flight football are sinking.
Eddie Howe's side looked short on confidence as they slipped to their third successive defeat without scoring a goal.
"The first goal was a big shift, up until then it was two quite even teams," Howe told BBC's Match Of The Day. "I'm not going to blame anybody, we are trying to do the right thing and just haven't executed it very well.
"Confidence, nerves, it is such a key thing - we have been on a difficult run and this week key players have got injured.
"We are not looking free-scoring and when you concede a goal it seems a long way back. We need to focus on both disciplines."
Sunday's setback against a club who had spent the entire season in the relegation zone was their ninth defeat in their last 11 matches since beating Manchester United on November 2.
Bournemouth have taken just four points in that period and are second bottom. Unless Howe can stop the rot they are heading for relegation.
"The manager always has to take responsibility when things aren't going well. Instilling confidence back to the players is my job," Howe said.
They are second bottom with 20 points from 22 games having been as high as seventh in early November.