Watford boosted their Championship play-off hopes as Moussa Sissoko's goal ended Swansea City's unbeaten run under Alan Sheehan.

Sissoko made Swansea pay after Goncalo Franco's glaring error, the Watford skipper stroking home first time from Tom Ince's pass.

Swansea had their moments, with Zan Vipotnik going closest for a visiting side who will feel they should have claimed a point, but the Hornets battled hard to hold on for just the second win in their past eight home games.

Victory means Watford climb to 10th, with the gap to sixth-placed Coventry City cut to four points with nine games remaining.

Defeat was Swansea's first in four matches - and their first since caretaker boss Sheehan took the reins following the departure of Luke Williams last month.

Swansea remain 16th in the table, nine points clear of the relegation zone.

Watford boss Tom Cleverley - who celebrated a year in charge this week - had urged his players to dig deeper than they have all season on the back of defeat by Millwall last time out.

Yet it was thanks largely to an inexplicable error from Franco - one of Swansea's top performers this season - that they shaded a tight contest.

Franco had almost played a part in an early Swansea opener, when he dispossessed Giorgi Chakvetadze and teed up Vipotnik for a fierce shot which was pawed to safety by Egil Selvik.

Watford's goalkeeper was on hand once more to save when Vipotnik ought to have done better with a header from Josh Key's whipped cross.

At the other end, Ince headed off target and Yasser Larouci dragged wide before the goal came as a result of Franco's pass to a team-mate who was not there.

The ball rolled instead to Ince, whose simple ball allowed Sissoko to beat Lawrence Vigouroux with an arcing shot which flew high into the corner of the net.

Having conceded for the first time since Sheehan took charge, Swansea almost conjured a response in first-half stoppage time when Liam Cullen headed just over from Josh Tymon's corner.

Watford might have stretched their advantage after the break, with Ryan Andrews flashing narrowly wide and Edo Kayembe's long-ranger dipping over the bar.

But Swansea kept on coming, with Eom Ji-Sung hitting the side-netting before Cullen's header hit Mattie Pollock and looped over the bar.

Watford did just enough to soak up the pressure - and ensure they remain firmly in the play-off race.

Watford head coach Tom Cleverley:

"I don't think it's sustainable to be honest, how we are managing games. I am quite angry with how we managed the game.

"The application from pretty much everyone is to the maximum but I just think we can manage the game better. We can't keep putting these games to chance.

"The first-half performance was fantastic and the second half we looked like a team that's tired and making poor decisions. We need to address it as soon as possible.

"We have to demand more from ourselves because to reach our goals. I am not sure if today's second-half performance would help us do that."

Swansea caretaker boss Alan Sheehan:

"Franco turned the ball over. He thought that it was one of his team-mates but it was one of theirs, but Franco has been outstanding for us.

"We appreciate him so much, what he gives to the team. That's the way it is, somebody makes a mistake, we lose the game, but nothing is on him at all.

"We are a team, we win as a team and lose as a team and I think we are quite unfortunate to be walking out of here with zero points, but that's the nature of it and we get ready for Saturday [against Burnley].

"Again [Swansea's fans] have seen a team tonight giving absolutely everything - we just lacked a small bit of quality. I wish we could have got at least a point tonight and on another night you never know."