Leyton Orient forward Josh Koroma beat the offside trap to score a 63rd-minute winner at Plymouth.
Koroma latched on to Ollie O'Neill's defence splitting volleyed through ball before firing low into the corner past Luca Ashby-Hammond.
As anticipated new Argyle central defender Alex Mitchell made his debut just a day after joining the Greens on a season-long loan from Charlton.
Argyle showed their intent from the off with right back Kornel Szucs breaking through on the right before sending a tame shot at goal in the sixth minute.
Orient keeper Tommy Simkin, diving to his right, brilliantly palmed away Caleb Watts' goalbound volley following Xavier Amaechi's cross from the right in the 14th minute.
Striker Aaron Connolly pounced on an error by Argyle central defender Brendan Galloway forcing Ashby-Hammond to save at his near post as he drove in from the right and let fly in the 32nd minute.
Connolly's 34th-minute effort, after latching on to another poor defensive back pass, was easily saved.
In the 49th minute Connolly teed up Diallang Jaiyesimi, who fired over from 10 yards out.
Report supplied by PA Media.
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