Striker Marino Keith bagged a dramatic last-gasp winner to keep Plymouth's automatic promotion push on course, after Swindon had fought back from two down with two goals in the final 10 minutes.
Joint leading scorer Keith settled a pulsating match two minutes into stoppage time just seconds after Swindon mid fielder Steve Robinson had been sent off.
Keith smashed in his ninth goal of the campaign with virtually the last kick of the match to cancel out Swindon's late heroics.
The gangly front man beat Swindon goalkeeper Rhys Evans from ten yards out after the Swindon defence had failed to deal with Plymouth captain Paul Wotton's long ball.
The Pilgrims had the better of an open first half and took a deserved lead through midfielder Tony Capaldi on 12 minutes.
Capaldi fired in to the bottom corner after full-back Paul Connolly had crossed from the right.
Keith came within inches of making it 2-0 seven minutes before half time with a speculative 25-yard shot that flew past the post.
Robins defender Matt Heywood almost marked his return from a one-match ban with a goal 13 minutes in to the second half when he headed against the post.
Swindon were denied by the woodwork again just two minutes later when midfielder Stefani Miglioranzi cracked the crossbar from 30 yards out.
Miglioranzi's misfortune was compounded 16 minutes later when Plymouth midfielder David Norris doubled the visitors' lead.
Winger Norris fired home from eight yards out after being set up by substitute Micky Evans.
Rory Fallon gave Swindon some hope with his first goal for the club ten minutes from time and top scorer Sam Parkin seemed to have won his side a share of the spoils when he equalised in the final minute.
However, Swindon were reduced to ten men seconds later when midfielder Robinson was sent off for a second bookable offence, before Keith took advantage by grabbing the winner with virtually the last kick of the match.