Match ends, Cardiff City 2, Watford 4.
Watford came from behind to beat Cardiff and extend their opponents' winless run to five games.
Adam Le Fondre's header gave Cardiff the lead, but Adlene Guedioura's volley and an Odion Ighalo header gave Watford a 2-1 half-time lead.
Guedioura's 30-yard effort and Gabriele Angella's header then secured the visitors' fourth win from five matches.
Kenwyne Jones headed Cardiff's second in injury time, but it was in vain and the home side were booed off the pitch.
Cardiff's third defeat in five games prompted a furious response from some of the Championship club's fans, who called for manager Russell Slade to be sacked after Watford scored their fourth.
The Bluebirds' last win came against Watford in November, when a Le Fondre goal secured their only away triumph of the season so far.
The former Reading striker struck again to put the Bluebirds ahead at the Cardiff City Stadium, meeting Peter Whittingham's in-swinging free-kick with a glancing header into the bottom corner.
Le Fondre could have doubled Cardiff's lead five minutes later but he prodded a weak shot straight at Watford goalkeeper Heurelho Gomes.
While Cardiff created the clearer scoring chances, it was Watford who controlled possession with their five-man midfield.
They had to wait until the 42nd minute, however, for their first real opportunity and they took it well as Gianni Munari's chipped cross was hooked in by Guedioura.
Watford's comeback was complete on the stroke of half-time, as Daniel Pudil crossed for Ighalo to head in firmly from close range.
Cardiff were booed off the pitch at the break and the home crowd's mood worsened after the restart.
Slade's decision to replace midfielder Tom Adeyemi, who had been one of the stand-out players, was met with chants of disbelief from the Cardiff fans.
Watford seized on the tense atmosphere and the Hornets extended their advantage as Guedioura thumped a fierce 30-yard shot into the top corner.
The visitors compounded Slade's misery with a fourth goal when Angella headed in from substitute Troy Deeney's cross.
Jones headed in Cardiff's second goal in injury time, but the damage had been done to heap further pressure on Slade, who was appointed in October.
Cardiff manager Russell Slade: "The fans are entitled to their opinions and when the team is not playing well, as we are, then you have to expect that situation to arise.
"It's inevitable that you come under pressure when results are not going your way and it's frustrating at times for us.
"I'm sure that the owner, like me, is not over-enthralled with the results right now. But I have to be tunnel-visioned and we will keep working hard."
Watford head coach Slavisa Jokanovic: "I'm happy with the team performance. We played and fought like a team even after making six changes to keep the team fresh. That was the most pleasing thing.
"The last performance against Wolves was the worst since I arrived at the club but here we showed good skill. But it is only one game. You cannot play well in one game and then badly the next. We need more consistency."
- 5Ecuele Manga
- 18AdeyemiSubstituted forK Harrisat 61'minutes
- 17GunnarssonSubstituted forRallsat 61'minutes
- 10Le FondreSubstituted forMachedaat 77'minutes
- 3da Silva
- 40K Harris
- 14ParedesSubstituted forAnyaat 71'minutes
- 22AbdiSubstituted forTozserat 78'minutes
- 11ForestieriSubstituted forDeeneyat 82'minutes
- Stuart Attwell
- Shots on Target
Second Half ends, Cardiff City 2, Watford 4.
Corner, Cardiff City. Conceded by Adlène Guédioura.
Attempt missed. Craig Noone (Cardiff City) left footed shot from outside the box is close, but misses the top right corner. Assisted by Peter Whittingham.
Attempt saved. Odion Ighalo (Watford) left footed shot from the centre of the box is saved in the centre of the goal. Assisted by Troy Deeney with a cross.
Attempt blocked. Odion Ighalo (Watford) right footed shot from the centre of the box is blocked. Assisted by Troy Deeney with a through ball.
Goal! Cardiff City 2, Watford 4. Kenwyne Jones (Cardiff City) header from the centre of the box to the top right corner. Assisted by Craig Noone with a cross.
Offside, Watford. Adlène Guédioura tries a through ball, but Odion Ighalo is caught offside.
Offside, Cardiff City. David Marshall tries a through ball, but Federico Macheda is caught offside.
Attempt saved. Sean Morrison (Cardiff City) header from the centre of the box is saved in the top centre of the goal. Assisted by Peter Whittingham with a cross.
Corner, Cardiff City. Conceded by Ikechi Anya.
Corner, Cardiff City. Conceded by Gabriele Angella.
Gianni Munari (Watford) wins a free kick in the attacking half.
Foul by Peter Whittingham (Cardiff City).
Goal! Cardiff City 1, Watford 4. Gabriele Angella (Watford) header from the centre of the box to the top left corner. Assisted by Troy Deeney with a cross following a corner.
Substitution, Watford. Troy Deeney replaces Fernando Forestieri.
Corner, Watford. Conceded by Bruno Ecuele Manga.
Tommy Hoban (Watford) wins a free kick in the defensive half.
Foul by Federico Macheda (Cardiff City).
Substitution, Watford. Daniel Tözsér replaces Almen Abdi.