With Chelsea, Manchester City and Liverpool next on the horizon, Sunderland were dealt a mighty blow to their hopes of improving their survival prospects by the turn of the year.
The 1-0 loss to a Watford side now boasting 25 points keeps Sam Allardyce's side rooted to second bottom spot after Sunderland paid the price for a snail-paced start when they could easily have been 3-0 down inside the opening 15 minutes.
Odion Ighalo's fourth minute striker was enough for the Hornets, but that prompted a deluge on the Sunderland goal before Allardyce was forced to bring on Jack Rodwell and abandon his 5-4-1 set-up.
Fabio Borini had Sunderland's best chance of levelling before the break, but it wasn't until the introduction of Jermain Defoe for the finale when the Black Cats genuinely looked like getting anything.
Defoe was denied by a brilliant save from Heurelho Gomes, before sending an effort agonisingly wide of the post with six minutes to go.
Sunderland were a dealt a blow before kick-off when Younes Kaboul was forced out through illness, with full-back Billy Jones taking the French international's spot at centre-half on the left-hand side of the back three.
But Watford exploited that change with less than four minutes on the clock when Allan Nyom got in behind the Sunderland defence to the right-hand by-line and pulled it back low into the six-yard box.
Odion Ighalo got ahead of Sebastian Coates and the ball deflected off both players, before beating Costel Pantilimon from four yards out.
There was almost a second for the Hornets in the ninth minute, as they again preyed upon Sunderland's weaknesses down the flanks.
Nathan Ake got the wrong side of DeAndre Yedlin and lifted it to the back post, where Almen Abdi nicked the ball away from Patrick van Aanholt, before his effort from six yards out was blocked behind.
Watford continued to rip the Sunderland defence to pieces and somehow failed to net a second in the 12th minute after Ighalo left John O'Shea trailing with a turn down the right-hand side of the area.
Ighalo's shot was parried by Pantilimon and cleared off the line by Coates, before an almighty goalmouth scramble eventually resulted in Jose Manuel Jurado cracking a shot against the outside of the post.
Sunderland were a whisker away from a leveller five minutes later when Yann M'Vila picked out the run of Fabio Borini with a lovely chipped pass and the Italian beat Miguel Britos down the right-hand side of the area.
Borini's shot across goal was a good one, but it skipped an inch wide of the far post.
Such was Watford's attacking threat, Sam Allardyce made a change in just the 19th minute, with Jack Rodwell replacing DeAndre Yedlin, as Sunderland reverted to a 4-3-3.
Pantilimon then had to produce a smart save to parry away Etienne Capoue's shot after an awful giveaway midway inside his own half by Steven Fletcher.
Sunderland went close to a leveller two minutes before the interval when M'Vila's free-kick flicked off the head of Watford defender Miguel Britos, before Heurelho Gomes tipped it over the bar.
Seven minutes after the restart, Rodwell tested Gomes with a left-footed stinger from 20 yards that the ex-Spurs keeper pushed away to his left.
There was plenty of huff and puff from Sunderland in the search for an equaliser, but little quality - Watmore swerving a shot wide of the post with 13 minutes to go.
Pantilimon then kept Sunderland in it when he blocked at the feet of Ighalo after Coates had missed the ball to leave the Watford striker in behind.
At the other end, substitute Jermain Defoe then saw an off-balance right-foot shot brilliantly parried behind by Gomes at his near post.
Then with six minutes to go, van Aanholt's volleyed low cross from the left was flicked by Defoe, but the ball drifted agonisingly wide of the far post.
Fellow substitute Adam Johnson should have grabbed an equaliser with a minute to go, but sent his half-volley wide after M'Vila's cross had picked him out at the far post.
Sunderland: Pantilimon, Yedlin (Rodwell 19), Coates, O'Shea, Jones, van Aanholt, M'Vila, Toivonen, Watmore, Borini (Johnson 57), Fletcher (Defoe 71). Subs not used: Mannone, Matthews, Lens, Graham. Booked: Rodwell (60)
Watford: Gomes, Nyom, Cathcart, Britos, Ake, Capoue, Watson, Abdi (Guedioura 69), Deeney, Jurado (Anya 76), Ighalo. Subs not used: Arlauskis, Paredes, Berghuis, Diamanti, Oulare