DIOMANSY Kamara's sizzling scoring streak continued as his 16th and 17th goals of the season edged Albion towards an eighth successive Hawthorns win - and crucially within one point of second spot.
The Senegal pace ace's stunning goals return has come from just 21 starts.
And he underlined his worth to the Baggies' promotion hopes by converting a 41st-minute penalty and netting a stunning 50th-minute second.
Argyle made Tony Mowbray's men sweat after sub Rory Fallon's first Pilgrims goal reduced the arrears in the 71st minute.
The Baggies had to survive a penalty-box barrage - plus two strong spot-kick appeals - during the closing stages but managed to hold on for a fifth successive win.
Albion, spurred on by the energetic Richard Chaplow, were far less impressive than at Molineux on Sunday but showed real battling qualities to end the Pilgrims' six-match unbeaten run.
After the euphoria of the brilliant Black Country beating of Wolves, it was back to the bread and butter of the Championship as Ian Holloway's 11th-placed side came to town.
New boy Dean Kiely was handed an instant debut between the sticks - with Pascal Zuberbuhler missing out altogether - in Mowbray's only change from the FA Cup win.
Fellow new arrival Sherjill MacDonald was named on the bench.
Plymouth made an assured start under the floodlights as they kept Albion pegged back during the opening stages - but without troubling Kiely.
And it was Albion who created the game's first telling moment in the 11th minute.
Kamara controlled Paul Robinson's ball over the top before skipping past Argyle duo Hasney Aljofree and Lilian Nalis to race into the box.
But as Pilgrims keeper Luke McCormick advanced from his goal, the ex-Portsmouth hitman was crowded out in the box and had the ball stolen off his toes as he shaped to shoot.
Kamara was in the thick of it again 60 seconds later when he directed Jason Koumas' dangerous centre inches wide of the right-hand post following strike partner Kevin Phillips' clever dummy.
Plymouth were still enjoying plenty of possession but lacked a cutting edge in the final third.
And it was Albion who went close again in the 20th minute when Paul McShane saw a brave stooping header from Koumas' free-kick loop onto the roof of the Plymouth net.
The Pilgrims finally recorded their first effort on goal moments later when Peter Halmosi whipped a right-footed free-kick towards the top right-hand corner - but Kiely was there to gather above his head.
Albion surged straight upfield and won a set-piece in a similarly dangerous position, which Koumas whipped inches past the far post.
A neat left-wing move then set up a shooting chance for Robert Koren - making his first home start - 25 yards out, but the Slovenian international's effort flew straight into McCormick's arms.
The game descended into a long spell of inactivity as both sides struggled to keep possession.
But Albion brought The Hawthorns to life by snatching a 41st-minute lead.
The hosts were awarded a penalty when Akos Buzsaky handled in the box after McShane had flicked on Neil Clement's long throw-in.
In-form Kamara just about squeezed his spot-kick home. McCormick guessed the right way but saw the ball slip under his arm.
Albion endured one worrying moment before the break when Barry Hayles gave Clement the slip down the right.
B ut fellow centre-half Curtis Davies scented the danger and got across in the nick of time to block the striker's route to goal
In the dying seconds of the half, referee Mike Thorpe enraged the Plymouth bench when he waved play-on after Phillips had accidentally collided with a Plymouth defender.
The former Villa man isn't one to look a gift-horse in the mouth and whipped in a terrific right-wing cross to find Koren at the far post.
But the former Lillestrom maestro could not keep his diving header on target.
Plymouth started the second half in confident fashion and Albion were relieved to see Hayles fire wastefully over from inside the box after Robinson had failed to cut out Nalis' lofted pass.
But the home hordes were on their feet in the 50th minute celebrating another Kamara wonder goal.
There looked nothing on when Phillips switched the ball from left to right.
But Kamara cushioned the pass and knocked the ball past Tony Capaldi in one sweet movement before skipping past Aljofree, drawing McCormick from his goalline and finishing with unerring accuracy from a tight angle.
It really was a goal to behold.
Albion now had the bit between their teeth and the unmarked Chaplow, who was covering every blade of grass, should have done better when he stabbed Koren's pinpoint cross over from eight yards.
Plymouth continued to work tirelessly for the cause and dangerman Buzsaky was only a whisker away with a ferocious 20-yard volley after Davies had only half-cleared David Norris' right-wing cross.
Albion were also grateful for Kiely's excellent positioning in the 64th minute, which allowed the former Charlton keeper to easily gather Aljofree's dangerous downward header from Capaldi's corner.
This was proving to be Plymouth's most dangerous spell and they pulled a goal back 19 minutes from time.
Sub Fallon had only been on the field for six minutes but showed terrific skill in chesting Capaldi's lofted ball into the box and volleying into the bottom right-hand corner.
Albion threatened again briefly when sub Zoltan Gera dragged a 20-yard effort just wide of the near post - but the remainder of the game belonged to Plymouth.
The Baggies were grateful to Kiely for a terrific point-blank save to deny unmarked sub Sylvan Ebanks-Blake in the box.
Moments later, the same player nipped in between Clement and Kiely to lift the ball over the Baggies keeper and towards the empty net, but Clement recovered in time to clear over his own bar.
Albion's hearts were well and truly in their mouths two minutes from time when sub MacDonald, a 76th-minute replacement for Kamara, appeared to trip Capaldi in the box.
But Suffolk official Thorpe waved the Pilgrims' vociferous penalty appeals away - much to Holloway's disgust.
Albion had one last scare when Norris rose to meet Paul Connolly's cross, only for the right-winger to head straight at Kiely.
The final whistle brought widespread relief around the Black Country venue as the home fans celebrated a hard-fought and vital victory.
ALBION (4-4-2): Kiely; McShane, C Davies, Clement, Robinson; Koumas (Gera 65), Chaplow, Greening, Koren; Phillips (Carter 85), Kamara (MacDonald 76). Subs not used: Daniels (gk), Hodgkiss.
PLYMOUTH (4-4-2): McCormick; Connolly, Seip, Aljofree, Capaldi; Norris, Buzsaky, Nalis, Halmosi (Sinclair 53); Hayles (Ebanks-Blake 73), Gallen (Fallon 65). Subs not used: Timar, Summerfield.
GOALS: ALBION - Kamara (pen 41 & 50). PLYMOUTH - Fallon (71).
BOOKINGS: ALBION - Robinson (foul 32), Chaplow (foul 52). PLYMOUTH - Aljofree (foul 12), Capaldi (foul 69), Nalis (foul 90+1).
REFEREE: M Thorpe (Suffolk).
ATTENDANCE: 19,894.
ALBION STARMAN: Richard Chaplow.
(PICS BY LAURIE RAMPLING)
