ARGYLE were confronted by one of football's harshest truths -indeed one of life's harshest - as they failed to fire for a fourth successive home game: when you are down on your luck, you do not get the breaks.
The Pilgrims deserved one for a thoroughly committed display that reached decent heights after the interval, but they came up against a goalkeeper in the form of his life. Scott Loach made two unbelievable saves, as well as a string of barely less credible ones, to thwart the Greens' best efforts.
Unfortunately, they also deserved little better than to go a goal behind in the fourth minute, during which time Tom Cleverley took advantage of a nervous, sluggish start to score the only goal of the game.
How Watford kept hold of that advantage for the next 90 minutes was a complete puzzle. Up until the interval, they were comfortable enough, especially with Loach in such good form, but, afterwards, they needed sponge-like qualities to soak up waves of Pilgrims' pressure.
On Saturday, after the Pilgrims had missed an open goal, hit the crossbar and been denied by a worldy save at West Browm, Paul Sturrock had said Pilgrims should not be thinking 'if only' any more, but there were so many if only moments again.
Argyle also hit a post, saw a goal-line clearance, and had a couple of chances which brushed the frame of the goal as they attempted to get back into the game.
Luggy had made four personnel changes to his starting line-up from the one that had started so gamely at West Bromwich on Saturday before being bounced by Marek Cech and going down, a shade unjustly, 3-1.
A lack of available defenders also saw the abandonment of the rather promising 3-4-3 seen for the first time at the Hawthorns, in favour of a solid 4-4-2.
David McNamee had recovered from flu to be restored to the restored back-four, with Krisztián Timár coming back to the colours for the injured Réda Johnson, and Gary Sawyer dropping back from midfield.
Captain Carl Fletcher by-passed him in transit to line up alongside Karl Duiguid in the centre of a four-man midfield to which Chris Clark was restored and Alan Gow added, the Scot adopting a wide role behind Saturday's goalscorer Jamie Macke and the recalled Cillian Sheridan.
Jim Paterson and Luke Summerfield were relegated to the substitutes' bench, while weekend starter Steve Maclean did not make the 18-man match-day squad.
Watford, arriving at Home Park unbeaten in five games, had no need to tinker with the men who had beaten bottom side Barnsley 1-0 at the weekend.
The starting 11 was the same, with an attack led by weekend scorer Danny Graham and on-loan Arsenal starlet Henri Lansbury. The only change came on the bench, where Jure Travner replaced Eddie Oshodi.
Not for the first time this season, a set-piece proved to be the Pilgrims' early downfall, as Argyle failed to get on to the front foot.
Watford's second corner of the match, in the fourth minute, was pinged low and hard by Don Cowie to the near post, where Cleverley's powerful shot from the angle of the six-yard box was deflected past Romain Larrieu off Sawyer.
The initial setback clearly sapped from Argyle what reservoirs of fragile confidence they had come into the game with, and one feared the worst.
Watford, conversely, rode their wave and, for long periods, the game was played in the Greens' defensive half.
It was something of a surprise, then, when Argyle came close to levelling. A clever mismove free-kick saw McNamee's delivery reach the head of Sheridan, who put the ball into the danger zone. From here, Mackie headed goalwards, only for goalkeeper Loach to acrobatically claw the ball away.
If that save was out of the topmost drawer, Loach's next was from the shiny polished surface above it. How he managed to scoop out Mackie's downward header from point-blank range is right up there with what happened to Lord Lucan among life's great mysteries.
The heads you lose scenario at least breathed some belief into the Pilgrims, and that was underlined by some neat passing that was obviously appreciated by a small, but largely supportive crowd.
The early goal, however, clearly undermined the Greens: to concede a second would have been fatal, and that thought was in their minds, but they needed to take that risk in pursuit of the equaliser.
Goals, it is said, change games and Cleverley's clearly affected this one. Watford did not have to chance their arm, and did not. Instead, they waited for the opportunity to kill off the game.
Their mission was enhanced by yellow cards to each of the Pilgrims' centre-backs - Timár and Árnason, and a third defender, McNamee - to add further jitters to a shaky back-four.
Watford's bullet-in-the-head moment nearly came when Cowie teed up Graham for a header that Larrieu clutched near his goal-line, and came closer after Lansbury's shot from the edge of penalty area beat Larrieu but rebounded to safety from a goalpost.
Luggy tweaked things at the interval to give Gow a more central role, and the Scot immediately set up Duguid for a shot from 20 yards that Loach was obliged to save, without too much trouble.
Mind you, nothing appeared to cause Loach too much trouble. He produced another world class save to deny the impressive Sheridan after the Irishman hooked a shot towards goal from inside the six-yard box.
The Greens continued to keep Watford under the thumb, and Árnason was inches from levelling with his first goal in English football as he powered Clark's corner wide, before Loach produced another fine save, from another threatening Clark corner, to keep out Sawyer's header.
It was all Argyle - and some Loach - but the goal their efforts deserved would not come. More pressure saw Sheridan head on a cross towards the far post, where Duguid stole in to head the ball against a post from barely two yards.
Luggy tried a three-card trick to finesse a goal, introducing Alan Judge, Rory Fallon and, for the first time at Home Park since he arrived in the halcyon days of summer, Bradley Wright-Phillips. Clark, Gow and, perhaps a tad unluckily, Sheridan made way.
The something-has-to-give feeling was enhanced by a run from Mackie that saw Lloyd Doyley head the ball out from under his crossbar.
Fallon was the next to suffer at the talented hands of Loach, who parried the new New Zealand international's diving header for a corner, from which Duguid's on-target volley was tipped over by the overused goalkeeper.
The Pilgrims kept their foot on the gas all the way to a fifth successive defeat and bottom spot in the Championship.
Argyle (4-4-2): 1 Romain Larrieu; 2 David McNamee, 5 Krisztián Timar, 11 Kári Árnason, 18 Gary Sawyer; 26 Alan Gow (10 Bradley Wright-Phillips 73), 4 Carl Fletcher (capt), 2 Karl Duguid, 6 Chris Clark (25 Alan Judge 73); 21 Cillian Sheridan (14 Rory Fallon 73), 8 Jamie Mackie. Substitutes (not used): 3 Jim Paterson, 20 Luke Summerfield, 23 Kyle Letheren (gk), 31 Yoann Folly.
Booked: Timár 27, Árnason 37, McNamee 43.
Watford: 1 Scott Loach; 33 Lee Hodson, 2 Adrian Mariappa, 17 Dale Bennett, 12 Lloyd Doyley; 7 Don Cowie, 28 John Eustace, 14 Ross Jenkins (18 Will Hoskins 90), 20 Tom Cleverley (15 Jon Harley 83); 5 Henri Lansbury (25 Nathan Ellington 68), 10 Danny Graham. Substitutes (not used): 3 Jure Traver, 16 Richard Lee (gk), 29 Michael Bryan, 31 Marvin Sordell.
Referee: Graham Scott (Oxfordshire).
Attendance: 8,703 (away 355).