Match ends, Watford 2, West Ham United 0.
Watford secured their second win in a row with victory over West Ham as Odion Ighalo continued his goalscoring form.
Ighalo turned home the opener after Nathan Ake robbed a dallying Andy Carroll in defence and crossed low.
The Nigerian doubled Watford's lead just after the break, firing home from Ikechi Anya's cut-back for his seventh goal of the season.
Enner Valencia intercepted Craig Cathcart's poor backpass but hit the post, before James Collins saw red.
The centre-back was dismissed for a foul on Ighalo, who was then replaced by Adlene Guedioura.
Watford's win, their second at home since promotion from the Championship last term, moves them up to ninth, while West Ham drop to fifth.
Andy Carroll's moment to forget
If Slaven Bilic had been wondering whether striker Carroll could cut it in defence he need wonder no longer - Watford's opener came from his mistake.
The striker sliced a clearance under no pressure at all, but still had time to clear with Ake bearing down. Instead though, he tried to turn the Watford man, who stole the ball and crossed to Igahlo.
Bilic will be wondering, too, why his team seem incapable of giving their best in matches they are expected to win.
Watford had scored and won just once at home this season, but this Hammers performance was a world away from their victories at Arsenal, Liverpool, Manchester City and Chelsea.
Former Blackburn striker Chris Sutton on Final Score: "I don't know what Andy Carroll was thinking? Just put your foot through it, get rid or put it out for a corner, anything.
"It's a dreadful mistake. I think he's tried a Cruyff turn in his own box. Never do that."
Man of the match - Odion Ighalo
Odion Ighalo is in the goals
Ighalo has now been involved in Watford's last nine Premier League goals, scoring seven and setting up two.
His partnership with Troy Deeney up front looks a real strong point for Quique Flores's Hornets, who followed up on their impressive victory at Stoke last weekend with another three points today.
If there was an element of slight fortuity about Ighalo's first goal - the cross might have eluded him had Aaron Cresswell not got a touch - his second goal was all power and purpose.
Smashed home past Adrian, it sucked the life out of the Hammers right after half-time and capped a deserved win for the home side.
Watford manager Quique Flores, speaking to BBC Sport: "I'm really pleased, very happy with the result and the performance.
"I think we enjoyed the game a lot. The players played with real confidence on the ball, with high pressure, it was an amazing performance.
"It's been important to change the mentality when you come in from a lower division, to win gives you the respect of the other teams."
West Ham manager Slaven Bilic, speaking to BBC Sport: "What happens weeks before and all the statistics is interesting but it doesn't mean a thing once the referee blows his whistle.
"From the start we were basically second best. They were better in every football department and totally deserved to beat us.
"We didn't have energy. They were quicker, more hungry than us. Today it was just that."
The stats you need to know
Odion Ighalo is now the highest scorer in Watford's Premier League history, overtaking Heidar Helguson and Hameur Bouazza.
This is the first time Watford have scored more than once at home in a Premier League game since April 2007 (4-2 v Portsmouth).
West Ham have received the most red cards in the Premier League this season with four.
This was West Ham's first league defeat at Vicarage Road since April 1985, having been unbeaten in 11 games at the ground since then.
The Hammers lost their first away game since the last day of last season (2-0 vs Newcastle).
- 2NyomBooked at 66mins
- 16AkéBooked at 81mins
- 29CapoueBooked at 85mins
- 21AnyaSubstituted forParedesat 68'minutes
- 22AbdiSubstituted forBehramiat 76'minutes
- 24IghaloSubstituted forGuédiouraat 86'minutes
- 5TomkinsBooked at 85mins
- 19CollinsBooked at 84mins
- 16NobleSubstituted forJelavicat 76'minutes
- 28LanziniSubstituted forZárateat 45'minutes
- 20MosesSubstituted forE Valenciaat 45'minutes
- 11E Valencia
- Keith Stroud
- Shots on Target
Second Half ends, Watford 2, West Ham United 0.
Corner, Watford. Conceded by Carl Jenkinson.
Attempt blocked. Troy Deeney (Watford) header from the centre of the box is blocked. Assisted by Juan Carlos Paredes with a cross.
Offside, West Ham United. Mauro Zárate tries a through ball, but Andy Carroll is caught offside.
Enner Valencia (West Ham United) wins a free kick in the defensive half.
Foul by Valon Behrami (Watford).
Offside, West Ham United. Aaron Cresswell tries a through ball, but Nikica Jelavic is caught offside.
Foul by Enner Valencia (West Ham United).
Adlène Guédioura (Watford) wins a free kick in the attacking half.
Attempt missed. Dimitri Payet (West Ham United) right footed shot from more than 35 yards misses to the right.
James Tomkins (West Ham United) wins a free kick in the defensive half.
Foul by Troy Deeney (Watford).
Hand ball by Enner Valencia (West Ham United).
Substitution, Watford. Adlène Guédioura replaces Odion Ighalo because of an injury.
Delay over. They are ready to continue.
Etienne Capoue (Watford) is shown the yellow card.
Delay in match Odion Ighalo (Watford) because of an injury.
James Collins (West Ham United) is shown the red card.
Foul by James Collins (West Ham United).