Goals from Barry Hayles and David Norris booked Coca-Cola Championship side Plymouth's berth in the FA Cup fourth round after League Two visitors Peterborough gave them a scare in the third-round replay at Home Park.
An upset had looked on the cards when Aaron Mclean fired managerless Posh into a 13th-minute lead but veteran Hayles responded within five minutes before Norris scored a fine solo effort.
But it was left to a stunning 87th-minute save from Argyle goalkeeper Luke McCormick to confirm a trip to fellow League Two side Barnet for Ian Holloway's side on January 27.
A long throw-in was only half cleared and in the melee centre-half Craig Morgan blasted in a shot from four yards which McCormick somehow turned over.
The visitors parted company with manager Keith Alexander yesterday following a run of six consecutive defeats in League Two and caretaker boss Tommy Taylor enjoyed a dream start to life in charge when they took the lead with their first attack.
Adam Newton threaded a ball into the area from the right and Mclean - who scored a late equaliser in the initial tie at London Road - drove in left-footed from 15 yards under the dive of McCormick.
But the lead was short-lived as Hayles notched his 10th goal of the season in the 18th minute.
Reuben Reid beat Shane Huke to the byline and his perfectly-weighted cutback found Hayles in space and he coolly tucked it past Mark Tyler from the penalty spot.
Hasney Aljofree then thumped a header straight at Tyler from a Tony Capaldi corner before Norris gave Argyle the lead in fine style in the 27th minute.
Peterborough striker Danny Crow saw his shot well blocked by Marcel Seip and Argyle launched a lightning breakaway down the right.
Reid found Hayles with an incisive pass and his square pass was collected superbly by Norris, who beat Mark Arber with ease before clipping over the advancing McCormick.
Taylor made a change at half-time with Peter Gain replacing Gavin Strachan in midfield and it almost proved worthwhile in the 49th minute.
A fine ball across the area from Gain picked out Richard Butcher but his firmly-hit strike was well held by McCormick.
Argyle's Hungarian midfielder Akos Buzsaky, who scored two superb free-kicks in the 3-1 win at Norwich last weekend, then brought a sprawling save from Tyler from fully 25 yards before Hayles was presented with a clear-cut chance to end the tie.
Norris was again the architect and after a driving run down the right his floated cross picked out Hayles perfectly, but he could only guide his volley straight at Tyler.
And Holloway's men were nearly punished for their wasteful finishing during a tense last 10 minutes.
First Morgan headed narrowly wide from Jamie Day's inswinging free-kick before McCormick's crucial intervention denied Morgan again in the dying minutes.
Teams
Plymouth McCormick, Connolly, Seip, Aljofree, Sawyer, Norris,Buzsaky (Summerfield 71), Nalis, Capaldi,Reid (Ebanks-Blake 60), Hayles.
Subs Not Used: Clapham, Hodges, Samba.
Booked: Aljofree, Ebanks-Blake.
Goals: Hayles 18, Norris 27.
Peterborough Tyler, Newton, Arber, Morgan, Huke (Yeo 63),Low (Benjamin 73), Butcher, Strachan (Gain 46), Day, Mclean,Crow.
Subs Not Used: McShane, Futcher.
Booked: Newton, Mclean, Morgan, Arber.
Goals: Mclean 13.
Att: 9,973
Ref: I Williamson (Berkshire).