Gerard Deulofeu scored Watford’s first top-flight hat-trick since 1986 as they boosted their hopes of a Europa League spot by cruising to victory at Cardiff.
Deulofeu put the Hornets in front on 18 minutes before two goals in the space of as many second-half minutes ended any hope of a fightback from the hosts, who played a role in their own downfall with some woeful defending.
The Spaniard opened the scoring after Bruno Manga gave the ball away, and doubled the advantage after a quick counter-attack. He completed his hat-trick after Harry Arter surrendered the ball tamely.
Deulofeu then set up Troy Deeney for a tap-in as Watford took a 4-0 lead.
Cardiff arguably could have done better for the visitors’ opening three goals, though they were aggrieved at 1-0 that they were not awarded what looked a clear penalty when Daryl Janmaat brought down Josh Murphy.
They did manage a consolation when Sol Bamba bundled home, but the four-goal margin was restored when Deeney scored his second from Will Hughes’ cross in injury time.
Victory sends Watford up to seventh while Cardiff remain 17th, though they could return to the relegation zone over the weekend.
Watford aiming for Europe
Many felt Watford would be in the lower reaches of the table this season along with Cardiff, but as March approaches they are seventh and through to the quarter-finals of the FA Cup.
They just about shaded the early exchanges here, though their opening goal was a gift from the hosts.
Cardiff failed to clear not once but three times, with Manga surrendering possession and Sean Morrison and Joe Bennett failing to win back the ball in a scrappy passage of play that culminated with Deulofeu sweeping home a precise, controlled finish.
As with the first, Watford’s second was as much about Cardiff’s poor defending as anything, with the Hornets countering from a set-piece and Deulofeu finishing after outpacing Manga and rounding Neil Etheridge.
He repeated the trick shortly afterwards. This time Arter surrendered possession and Deulofeu again had time and space to finish and score Watford’s first hat-trick in the top division since Mark Falco.
The 24-year old Spaniard capped a brilliant display with an assist for Deeney, who could not miss after a fine team move as he ended a run of eight games without a goal against the Bluebirds.
And Deeney was not done there, sweeping home from Hughes’ cross after Bamba had pulled a goal back by firing home from a rebound after his header hit the post.
Cardiff clobbered after emotional week
Cardiff manager Neil Warnock spoke this week about the need to perform in “12 cup finals” but their preparation was again overshadowed by the fallout over the transfer of Emiliano Sala.
Sala was Cardiff’s record signing but never played for the club – he died when a plane piloted by David Ibbotson, who remains missing, crashed.
Warnock said the £15m transfer could have been better conducted, but that chairman Mehmet Dalman “will do things in the right way”.
Cardiff now look to Everton loanee Oumar Niasse as their main goal threat, but he was found wanting just before Watford’s opener as he poked the ball straight at Ben Foster after stealing in behind the visitors’ defence.
Winger Murphy also looked lively – firing straight at Foster from a decent position – and thought he should have been awarded a penalty on the stroke of half-time.
Bluebirds boss Warnock could not get over “the injustice of it”.
He told BBC Match of the Day: “Troy Deeney and all their staff told us it was a stonewall penalty. I had to try and get it out of their minds at half-time.
“When everyone from the opponents tell you and deep down I think all the officials knew really. I think the referees guess a lot of the time and you can’t do that at this level.”
The Bluebirds were attempting to win three consecutive top-flight league games for the first time since February 1961, but Watford’s opening goal appeared to dent their confidence and they never recovered.