Aiden O'Brien capped off a dramatic turnaround as Millwall came from behind to beat Plymouth 3-2 in the second round of the Carabao Cup.
Jamie Ness' header was cancelled out by a Shaun Williams penalty, before Freddie Ladapo's fine goal restored Argyle's advantage.
Lee Gregory equalised seven minutes from time before fellow substitute O'Brien nudged home to send Millwall through.
The visitors started the brighter as a neat exchange with Antoni Sarcevic allowed Ness through on goal, but he was smothered by goalkeeper Ben Amos.
Argyle made the breakthrough four minutes before half-time as Ryan Edwards flicked on Conor Grant's corner straight into the path of Ness who was able to loop his header beyond Amos.
The hosts equalised in the 64th minute courtesy of a Williams penalty after Tom Elliott was dragged down by Edwards just inside the box.
Argyle responded five minutes later as Williams was dispossessed in midfield, allowing Ladapo to burst away from Murray Wallace to slot home.
Millwall pushed and found an equaliser in the 83rd minute as Jiri Skalak's cross was powered home by Gregory.
The comeback was complete in the 89th minute as O'Brien ghosted into the six-yard box to guide Shane Ferguson's tantalising cross beyond Matt Macey.