ALBION ended their three-game winless league run in style by putting the in-form Pilgrims to the sword.
Sub Zoltan Gera broke the deadlock in first-half stoppage time when he slotted home his eighth of the season.
Ishmael Miller marked his first start in three games by looping home his 12th of the term just before the hour mark.
And Roman Bednar - who else - well and truly brought Plymouth's four-game winning streak to an end by making it 16 goals in as many starts in the 67th minute.
The Baggies were full value for their 11th home win of the season, which completed the double over Paul Sturrock's side.
Albion started the day just three points and one place better off than Plymouth as fourth entertained fifth.
Mowbray made three changes, with Miller, Filipe Teixeira and Chris Brunt coming in for injured duo Kevin Phillips and James Morrison, plus the benched Gera.
A minute's applause was staged moments before kick-off in honour of 1954 FA Cup winner Jimmy Dugdale, who died this week aged 76. Both teams also wore black armbands as a tribute.
Efforts at goal were at a premium during the opening minutes as both teams sized each other up.
It wasn't until the tenth minute that anyone threatened when Miller pounced on Robert Koren's lay-off and burst between Paul Connolly and Krisztian Timar.
The ex-Manchester City striker would have had a clear sight of goal had he not taken such a heavy touch, providing onrushing Argyle keeper Luke McCormick with an easy save.
The Baggies were forced into an early change when Teixeira fell awkwardly after an innocuous clash with Pilgrims left-back Gary Sawyer and had to be stretchered off in the 18th minute. He was replaced by Gera.
Albion almost snatched the lead two minutes later.
Bednar did well to tee up Miller from Carl Hoefkens' hanging header and the powerhouse striker curled just wide from 18 yards.
Albion were doing all the pressing but found it difficult to break through the visitors' stubborn resistance.
Plymouth put the Baggies goal under a short spell of pressure by winning three successive corners, but the hosts stood firm.
The half, which had largely been a non-event, appeared to be petering out - until Albion broke the deadlock in the first minute of stoppage time.
Bednar's never-say-die attitude saw him pounce on Russell Anderson's poor back pass and round McCormick.
The Czech international could only find Nadjim Abdou as he pulled the ball back from the byline, but the Argyle midfielder fluffed his clearance to present Miller with a chance.
The Baggies No.17 saw his shot parried by McCormick but Gera pounced on the rebound to slot into the empty net.
There was still time for Argyle to go close at the other end, with Lilian Nalis directing a near-post header from Gary Teale's corner into the side-netting.
Albion started the second half on the front foot and Miller was unlucky to see his 20-yard drive deflect off Connolly and loop inches over the bar after charging past Anderson.
Brunt swung the ensuing corner deep into the Argyle box. Martin Albrechtsen headed it back across the face of goal and central-defensive partner Leon Barnett nodded just wide.
The action swung to the other end and Albrechtsen had to make an important block to prevent Peter Halmosi's 15-yard snapshot troubling Dean Kiely.
Back came Albion and Miller looked certain to score as he raced onto Paul Robinson's throughball and bustled his way past Anderson.
But the Baggies forward got the ball stuck between his feet as he attempted to round McCormick and the Argyle keeper managed to toe poke it to safety.
However, Miller made up for the miss just 60 seconds later when he fired Albion 2-0 up in the 59th minute.
The £900,000 signing showed terrific strength to hold off Anderson on the edge of the Plymouth box and, with his back to goal, hooked the loose ball over the stranded McCormick and inside the far post.
That proved Miller's last action as he was replaced by Luke Moore in the 63rd minute.
It was game, set and match to the Baggies in the 67th minute when Bednar made it 3-0.
Gera headed Jonathan Greening's deep cross back into the six-yard box and the on-loan Hearts man poked the ball past McCormick.
Albion almost made it four moments later when Brunt's crossfield ball presented Gera with a clear sight of goal.
As the Hungarian pulled the trigger, Sawyer risked life and limb to divert the shot away from goal.
Albion were now in complete control and Barnett wasn't too far away with a towering header from Brunt's corner.
A slick Baggies move then saw Koren cut inside Nalis before curling just wide from 18 yards as Albion saw out a comfortable win.
ALBION (4-4-2): Kiely; Hoefkens, Barnett, Albrechtsen, Robinson; Teixeira (Gera 18), Koren, Greening, Brunt; Miller (Moore 63), Bednar (Kim 71). Subs not used: Martis, Beattie.
PLYMOUTH (4-4-2): McCormick; Connolly, Timar (Seip 65), Anderson, Sawyer; Teale (Mackie 65), Abdou, Nalis, Halmosi (Clark 69); Easter, MacLean. Subs not used: Larrieu (gk), Wotton.
GOALS: ALBION - Gera (45+1), Miller (59), Bednar (67).
BOOKINGS: ALBION - Barnett (foul 90).
REFEREE: U Rennie (South Yorkshire).
ALBION STARMAN: Zoltan Gera.