David Moyes suffered a miserable start to his West Ham United reign as Watford eased to a 2-0 win over the Premier League strugglers on Sunday.
Moyes was in charge of West Ham for the first time following his appointment as replacement for the sacked Slaven Bilic.
But the former Manchester United boss was unable to spark an immediate upturn in his new club's fortunes.
Will Hughes put Watford ahead in the first half at Vicarage Road and Richarlison's strike after the interval extended West Ham's winless league run to five games.
The Hammers remain third bottom of the table, one point from safety, after Moyes got a first-hand look at the problems which cost Bilic his job.
Desperate to rehabilitate his reputation after overseeing Sunderland's relegation from the Premier League last season, Moyes has accepted a short-term contract with West Ham.
His failures at Sunderland, Manchester United and Real Sociedad have tarnished the fine work he did at Everton and the Scot can ill-afford another flop on his CV.
On the evidence of West Ham's lacklustre showing on his debut, Moyes has much work to do to lead his side -- who have lost three of their last five games -- away from the relegation zone.
After three successive defeats, Watford's comfortable victory showed why Everton have been trying to lure Hornets boss Marco Silva to Goodison Park.
Watford have so far rebuffed Everton's interest in former Hull City manager Silva, who has only been in charge since the close season.
He has already made a big impact in that time and Watford were quick to take the game to the wounded Hammers.
Hughes opened the scoring in the 11th minute, the midfielder slotting home from Andre Gray's scuffed shot after West Ham's defence were prised open far too easily.
Watford threatened a second goal when Gray linked up with Richarlison on the edge of the area.
The Brazilian's low shot was pushed away by Joe Hart, with Kiko Femenia dragging the rebound wide.
Cheikhou Kouyate had a chance to equalise, but the West Ham midfielder's drive was repelled by Heurelho Gomes.
Gomes did even better moments later as the Watford keeper kept out Marko Arnautovic's effort and then blocked his attempt from the rebound.
When Kouyate blazed over early in the second half, Moyes turned away in disgust.
Moyes was shaking his head in frustration again in the 64th minute.
Hughes got away with a handball, triggering the move that ended with Richarlison dancing past Winston Reid and firing in a low shot that beat Hart's weak attempt to save.
Rubbing salt into Moyes' wounds, Arnautovic was forced off after landing awkwardly on his arm in the closing stages.