Dundee slumped to their second league defeat on the spin as Dunfermline closed the gap between the sides to one point.
The Dark Blues were miserable at East End Park as Ryan Dow and Kevin Nisbet goals saw the Pars run out deserved 2-0 winners.
The result leaves Dundee clinging onto fourth spot in the Championship table by their fingernails.
Dundee showed two changes from the 3-0 Scottish Cup loss to Motherwell at Dens last weekend, with 17-year-old Lyall Cameron and Ross Callachan making their first starts in place of Shaun Byrne and Jamie Ness.
Callachan was endearing himself to the away support with energetic running and crunching tackles, while young midfielder Cameron didn’t look out of place playing off the right.
Dunfermline swung in a couple of early free-kicks and a corner, which came to nothing.
After a bit of a slogfest of an opening quarter, the game began to settle down, with the Dark Blues enjoying plenty possession.
Chances were scarce, however, with the first clear-cut opportunity of the game coming in the form of the opening goal on 28 minutes.
Kilmarnock loanee Dom Thomas surged past Cammy Kerr on the left and swung in an inviting delivery for Ryan Dow to head beyond Jack Hamilton.
It was the former Dundee United man’s sixth goal of the season and one that seemed to spark the Pars into action.
And it was another former United man, skipper Paul Paton, leading the way. His ferocious effort from fully 30 yards narrowly sailing over the crossbar just before the interval.
Moments later, though, it was 2-0 to the Fifers with talisman Kevin Nisbet notching his 22nd of the term.
And it was a terrific effort, coming off the left and leaving a trail of Dundee defenders in his wake before swerving home a wicked right-foot shot into the corner of the net
In an attempt to turn the tide, manager James McPake rolled the dice at half-time and sent on striker Danny Johnson for Cameron.
However, the Pars continued their onslaught with Dee No 1 Hamilton brilliantly tipping a Nisbet effort onto a post four minutes into the second period.
The prolific Pars No 15 flashed a volley wide just a minute later as the match threatened to run away from the Dark Blues.
The visiting Dees got their first look at new boy Ollie Crankshaw on 54 minutes as he replaced Paul McGowan.
Soon after, Jordan McGhee had their first shot of the match but his header was right at Cammy Gill in the home net.
However, for the next 20 minutes it was all Dunfermline as they looked the more likely to score and kill the game as a contest.
Hamilton had to deny Nisbet in several occasions as McPake and the away support vented their anger towards the players.
Johnson fired wide late on, with Crankshaw looking the most likely to create something.
However, in truth, this one was never a contest and the misery continues to pile on for Dundee.
Dunfermline XI (4-4-1-1): Gill (GK); Comrie, Ashcroft, Devine, Murray; Dow (Thomson 88), Paton (C), Turner, Thomas; McGill (Ross 67); Nisbet.
Subs not used: Scully (GK), Morrison, Edwards, Todd and McCann.
Dundee XI (4-3-3): Hamilton (GK), Kerr, McGhee, Meekings, Marshall, McGowan (Crankshaw 54), Dorrans, Callachan; Cameron (Johnson 45), Hemmings, McDaid.
Subs not used: Ferrie (GK), Byrne, Robertson, Strachan and Forster.
Referee: David Munro.