Jimmy-Jay Morgan scored the only goal of the game as Peterborough claimed a first away win of the season with a 1-0 victory at Plymouth.
Argyle goalkeeper Luca Ashby-Hammond kept out Jacob Mendy's thumping angled shot from the right but could do nothing to stop Morgan's follow-up on the half hour.
Ashby-Hammond had saved a 23rd-minute penalty from Harry Leonard after he had tripped Morgan as he tried to take the ball around him.
Plymouth were convinced a 41st-minute Alex Mitchell header had crossed the line when Alex Bass palmed the ball onto the crossbar and it appeared to bounce down behind the keeper.
Bass made a brilliant first-half stoppage-time save to deflect Lorent Tolaj's header around a post.
Matty Sorinola sent a 25-yard drive inches wide in the 56th minute as Argyle went in search of an equaliser.
Bass made another good stop on the hour, keeping out Bali Mumba's long-range strike.
Tolaj's 62nd-minute scissor-kick effort beat Bass but crashed off the underside of the bar.
Dangerman Tolaj's audacious 30-yard attempt in the 75th minute was palmed around a post by Bass at full stretch but Peterborough hung on to secure back-to-back victories.
Match report from PA Media.
Plymouth head coach Tom Cleverley says his side's disallowed goal should have counted
Darren Ferguson: 'We looked a determined outfit'
