Valerien Ismael kicked off his Watford reign in magnificent style with a 4-0 win over QPR at Vicarage Road.
The red-hot Hornets produced a swashbuckling first-half display which saw them score all their goals inside 43 minutes as Rangers showed why many have tipped them to struggle to stay up this season under Gareth Ainsworth.
The visitors, who were without first-choice centre-backs Jimmy Dunne and Jake Clarke-Salter due to injury, handed a full senior debut to Joe Gubbins alongside recent signing Morgan Fox and both struggled to contain a rampant home side.
It took just 33 seconds for the Hornets to open the scoring when Tom Dele-Bashiru slotted past Asmir Begovic after a sublime reverse pass from the impressive Imran Louza caught out the flat-footed R's defence.
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Watford went close to adding a second when Vakoun Bayo met a James Morris cross only for Begovic to claw away his goalbound header.
And Louza doubled the hosts' lead with a curling effort from the edge of the box in the 20th minute.
Francisco Sierralta and Ken Sema both went close to scoring as Rangers kept conceding possession and found themselves under constant pressure from the home side.
That pressure finally paid off again when Matheus Martins darted in front of Paul Smyth to nod home Sema's corner in the 38th minute.
The lively Bayo then made it 4-0 two minutes before half-time when he fired home at the back post from a low Sierralta cross, with the Rangers defence once again in disarray.
Bayo almost added a fifth in the seven minutes of first-half stoppage time after outpacing Fox to race on to a long ball over the top, but his lob landed on the top of the net.
QPR, who were booed off by a packed away end after a chastening opening period, saw beleaguered boss Ainsworth bring on Sinclair Armstrong and Stephen Duke-McKenna for the ineffective Smyth and Charlie Kelman.
Republic of Ireland U21 international Armstrong should have pulled one back for the Hoops when he got in behind the Watford defence, but was unable to turn the ball into the net from a tight angle in what was Rangers' only chance of note.
Almost immediately the Hornets went close to a fifth goal when the impressive Louza hit the crossbar from distance before making way in a triple substitution from Ismael to a well-deserved standing ovation from the home crowd.
Rangers did manage to stop the bleeding in the second half as Watford were denied by two late smart saves from Begovic but they slumped to the biggest defeat in a season opener since 2012 - a campaign that saw them relegated from the Premier League.
The managers
Watford's Valerien Ismael:
"I knew the guys were ready, we worked hard for seven weeks so they gave us the feeling they were ready for the competition. I told them just to get their rewards, to put their attitude and intensity in the game. It was a perfect start for everyone, not about the result but more about the attitude to get the reward after seven weeks of hard work.
"The combination for the goals, we've worked on it for seven weeks, the positioning of the players, we attack together and defend together. It was the perfect first step but nothing more. But the way we scored the goals, the combinations, the positioning from the players, it was all very pleasing."
QPR's Gareth Ainsworth:
"I am not happy, we were behind after the first minute and sometimes you have to hold hands up and say you weren't good enough. We were not ready for that first half from Watford and we were torn apart at times. I thought we looked a lot better in the second half but on the day Watford were much better than us.
"We win and lose as a team, there is no finger pointing from me, it is down to me as the manager to put it right. We are favourites for the bottom of the league, but we will be better than we were last season where we scrapped it to stay up."