Crystal Palace recorded a third successive Premier League win for the first time since September after Troy Deeney's own goal consigned Watford to a 1-0 defeat on Saturday.
Deeney, the Watford skipper, headed a free-kick by Yohan Cabaye into his own net midway through the second half to send Palace four points clear of the relegation zone.
Sam Allardyce's Palace have won three successive Premier League games without conceding a goal for only the third time.
Watford remain seven points above the relegation zone in 13th place, but Walter Mazzarri's side have now gone four games without a win and have won just twice on their last 13 league outings.
Chances were at a premium in a dismal first half at Selhurst Park, where Jeff Schlupp replaced the injured Patrick van Aanholt at left-back for the hosts.
Palace were the first side to threaten, Mamadou Sakho heading over following a corner by fellow Frenchman Cabaye in the 11th minute.
But Watford striker M'Baye Niang was the only player to register a meaningful effort with a shot that was straight at Palace goalkeeper Wayne Hennessey.
Mazzarri was forced into a change at half-time as Valon Behrami, who had been struggling with a hamstring injury, gave way for Abdoulaye Doucoure.
Another change for the visitors followed as Nordin Amrabat replaced Daryl Janmaat for his first appearance since sustaining an ankle injury on New Year's Day.
Wilfried Zaha squandered a chance to put Palace ahead when he slipped past Craig Cathcart before firing over.
But the hosts went ahead in the 68th minute when a stretching Deeney headed Cabaye's free-kick into his own net.
Doucoure almost caught Hennessey out with an audacious attempt from 35 yards, but the Wales international pushed it away.
A clumsy touch from Christian Benteke robbed him of an opportunity to seal victory for Palace and Cabaye shot narrowly wide late on.
In a stoppage-time scare for the hosts, an error from Hennessey gave Niang a chance to snatch a share of the spoils, but the on-loan AC Milan striker blazed over.