Simon Walton's last-minute penalty secured League Two basement side Plymouth a win at Dagenham & Redbridge.
Matt Lecointe, 16, lit up a dull first half with his first goal for Argyle.
Conor Hourihane's spectacular volley increased their lead, before Scott Doe and Jon Nurse converted crosses from Damien McCrory to pull it round.
McCrory was then sent off for a foul on Isaac Vassell before Walton converted a 90th-minute spot-kick to earn Argyle's first away win of the season.
McCrory was playing against his old club, having been signed by Dagenham & Redbridge from Plymouth in February 2010.