But the returning Gary Sawyer saw his 84th-minute strike deflect off Mark Hudson and leave Bluebirds goalkeeper David Marshall with no chance.
The home side had previously enjoyed the better of the chances in what was a hard-fought encounter, with the Pilgrims showing plenty of spirit and determination.
Joe Ledley missed a great chance to snatch a share of the spoils in injury time but it was Argyle who snatched the points in front of 24,010 at the Cardiff City Stadium - the club's biggest Boxing Day attendance for 39 years.
Dave Jones named an unchanged line-up from the side that saw off Middlesbrough back on December 13, with a failure in Cardiff's undersoil heating at their new state-of-the-art stadium putting paid to last weekend's home clash against Leicester.
Argyle boss Paul Mariner was forced into two changes, with loanees Shane Lowry and David Gray returning to Aston Villa and Manchester United respectively - Sawyer and Luke Summerfield coming in.
The Pilgrims made a solid start in what was a scrappy opening to the encounter, with Reda Johnson's snap-shot the closest either side came to breaking the deadlock inside the first 10 minutes.
But, having spent the initial stages working off their turkey dinner, Cardiff soon burst into action and forced a series of good saves from Romain Larrieu.
Hudson was first to see his header turned over the bar by the Pilgrims keeper before stabbing wide at the back post from the resulting corner.
Larrieu then produced a second save of note to parry Peter Whittingham's 20-yard effort to safety after some neat build-up play from the hosts.
The encounter fell into a lull as the game approached the half-hour mark yet it remained as competitive as it was from the first minute.
Bluebirds keeper Marshall saved well from Alan Judge's strike with 36 minutes on the clock and, for all the well-worked approach play that followed, the chance proved to be the last of a competitive and enjoyable but ultimately goalless first half.
Jay Bothroyd turned well inside the area and fired narrowly over the bar within minutes of the restart before Michael Chopra, without a goal in his previous 10 displays, wasted a great chance to open the scoring.
The former Newcastle and Sunderland man was played clean through by Whittingham but got too much purchase on his lofted finish and could only watch as the ball sailed over.
Summerfield fired into the side netting at the other end before Chopra saw a cross-shot again land the wrong side of the woodwork on the hour.
Cardiff were starting to apply more pressure as the second half wore on, with a couple of further half-chances going begging.
Substitute Ross McCormack smashed a right-footed effort narrowly wide from 25 yards in the 75th minute, with the Scotland international then briefly clashing with Argyle centre-back Johnson.
The visitors understandably looked to close the game out in the latter stages before, out of the blue, Sawyer saw his strike deflected into the net to leave the home crowd stunned.
Ledley then shot wide from 12 yards in the third minute of injury time.