SIMON Cox returned to Albion's starting line-up with a bang as his 66th-minute winner saw the Baggies overcome a tricky Home Park pitch.
The former Swindon striker was deployed in midfield but that did not stop him grabbing his ninth of the term, which ensured Roberto Di Matteo's men stay second.
The Baggies' third successive win was built on their first clean sheet in seven league games - and a towering performance at the heart of defence by Gabriel Tamas.
Graham Dorrans, Albion's usually reliable penalty ace, could have secured a more comfortable finish to the match for the visitors.
But the Scotland international, who had netted four spot-kicks in the previous four games, saw his 83rd-minute penalty saved by David Stockdale.
However, the Baggies held on and their hard-fought victory was only marred by Jerome Thomas' second sending-off of the season in stoppage time, when he scythed down sub David McNamee.
Di Matteo made changes - one enforced - to his team for the first time in six games as he drafted in four fresh faces.
Joe Mattock came in for the injured Marek Cech (hamstring) at left-back in one of three defensive switches.
Gonzalo Jara and Jonas Olsson dropped to the bench and were replaced by Gianni Zuiverloon and Abdoulaye Meite respectively.
In midfield, Cox came in for Robert Koren, who was among the substitutes.
The Baggies' first effort on goal came within 30 seconds of kick-off when the recalled Cox found Chris Brunt inside and he lashed a low shot into the side-netting from 20 yards.
Five minutes later, the ball broke to Alan Judge at the back post and Albion had on-loan defender Tamas to thank for blocking the Argyle winger's goalbound volley with a last-gasp lunge.
The pudding of a pitch severely hampered Albion's passing game but, after a scrappy passage of play, the visitors went close again on 18 when Roman Bednar flicked on Dorrans' left-wing corner and Tamas nodded just wide of the near post.
Four minutes later, Judge threatened again for the Pilgrims when he curled a 25-yard free-kick a yard wide of the left-hand post.
A mix-up between Meite and Youssouf Mulumbu, as they attempted to clear the danger in the 28th minute, saw the ball drop for Damien Johnson, whose volley from just inside the box flew high and wide.
Bednar did well to hold off his man in the 35th minute and nod down Zuiverloon's aerial ball for Dorrans, whose left-footed shot flew straight at Stockdale.
A minute later, Cox dispossessed Damien Johnson deep in the Albion half and found Bednar down the right.
The Czech striker out-muscled Gary Sawyer and Reda Johnson before seeing Stockdale save his low 15-yard drive and Kari Arnason cleared the rebound for a corner.
In the 37th minute, referee Steve Tanner waved away Plymouth penalty appeals when Jamie Mackie took advantage of Zuiverloon's slip but could not find a way past the sturdy Tamas.
Paul Mariner was forced into a change deep into first-half stoppage time when Karl Duguid went down in the home box and was stretchered off. He was replaced by McNamee.
Within 40 seconds of the second half getting underway, Cox managed to wriggle free down the left and he centred for Bednar, who was just put off by Stockdale's challenge at the near post.
The ball bounced through to the back post where Sawyer cleared as Brunt closed in.
Moments later, Dorrans' goalbound shot from the edge of the area was deflected wide for a corner.
Arnason's long throw-in from the right caused Albion all sorts of problems in the 49th minute and the ball fell perfectly for Mackie 12 yards out, but the Pilgrims striker volleyed wastefully over.
Back came Albion - and they took the game by the scruff of the neck on 66 by snatching the lead.
A delicious ball by Dorrans out wide to Thomas enabled the former Charlton winger to swing in a dangerous cross from the left.
Bednar caused problems for Reda Johnson and Arnason and the ball popped up for Cox, who expertly volleyed home from ten yards.
Six minutes later, Arnason got on the end of Judge's free-kick but sent his 18-yard header straight at Carson.
Albion had a great chance to sew up a deserved three points seven minutes from time when Stockdale could only parry Brunt's fierce drive.
The ball fell to sub Luke Moore, who was felled in the box by McNamee.
Somerset official Tanner pointed to the spot but Dorrans, who had converted four penalties in as many games to the keeper's left, went the other way and the Plymouth stopper saved.
The game finished on a low note for the Baggies when Thomas was deservedly shown a straight red card for a lunge on McNamee.
But the ten men had little trouble seeing off Plymouth's late pressure to bag away win No.8.
PLYMOUTH (4-4-2): Stockdale; Duguid (McNamee 45+4), Arnason, R Johnson, Sawyer; Clark, Fletcher, D Johnson, Judge (Noone 67); Mackie, Fallon (Cooper 59). Subs not used: Larrieu (gk), Wright-Phillips, Barker, Summerfield.
ALBION (4-5-1): Carson; Zuiverloon, Meite, Tamas, Mattock; Brunt, Cox (Slory 87), Mulumbu (Jara 75), Dorrans, Thomas; Bednar (Moore 81). Subs not used: Kiely (gk), Olsson, Koren, Thorne.
BOOKINGS: PLYMOUTH - Sawyer (foul 87), D Johnson (foul 88), McNamee (90+3). ALBION - Meite (foul 35), Mattock (foul 52), Bednar (unsporting behaviour 76).
GOAL: ALBION - Cox (66).
SENDING-OFF: ALBION - Thomas (serious foul play 90+1)
REFEREE: S Tanner (Somerset).
ATTENDA NCE: 12,053 (2,004 Albion fans).
ALBION STARMAN: Gabriel Tamas.
PIC: COX IN THE BOX...Striker Simon celebrates his Home Park winner
