Tuesday's result against Scottish Premier League opposition did not flatter the home side in the slightest, having outfought, out-thought, and outplayed their supposedly more illustrious Fife neighbours.
East Fife were rewarded for an impressive opening with an early goal, with Bobby Linn firing past Paul Gallacher.
Dunfermline regrouped and levelled 10 minutes later as Liam Buchanan slid in to prod home from close range.
But East Fife took a deserved lead again 10 minutes into the second half. Dalziel was the scorer, crashing a super effort high past Gallacher from the edge of the box.
Dunfermline almost took the tie to extra-time with the last action of the game, with Steven Hislop having to clear off the line.
For the visitors, Martin Hardie and the SPL's joint leading marksman Andy Kirk were given a rest, although Kirk came on for the last 20 minutes, while there were chances to impress for the likes of Buchanan, Kevin Rutkiewicz and Steven McDougall.
East Fife boss John Robertson chose to make only two changes to the side which lost 3-0 at Arbroath; Scott Dalziel replacing Steven Campbell and Ryan Wallace taking the place of David Cowan.
It took just three minutes for the home side to announce their attacking intentions. A lofted Craig Johnstone through-ball sent Ryan Wallace clear on goal, but the finish was lacking finesse and flew over the bar.
It proved to be a temporary reprieve as East Fife took the lead moments later.
Austin McCann failed to deal with a hopeful punt up-field, allowing Dalziel to find Bobby Linn in space on the angle of the box. His initial shot was well saved by Gallacher but Linn reacted quickest to lash home at the second attempt.
Despite the early dominance of the hosts, Dunfermline managed to regroup for long enough to grab an equaliser.
Andy Barrowman managed to get a shot away from 18 yards after showing great strength to shake off Hislop, and Michael Brown could only parry the effort as far as the six-yard line, allowing Buchanan to race in and scramble the ball over the line.
It was a goal against the run of play as East Fife dominated the half.
The SPL side were expected to improve in the second period yet Robertson's charges were soon ahead.
Dalziel steadied himself on the edge of the area to launch a superb right-footed drive high past Gallacher after a sweeping move from the lively home side.
Consecutive free-kicks from identical positions on the edge of the box could have made things worse for the Pars, with Gallacher saving from Linn's curler, before substitute Robert Sloan fired his own effort over the bar.
East Fife should have been out of sight, as chances for Linn and Wallace came and went, and there was almost a sting in the tail, with Hislop dramatically clearing off the line following a scramble with the very last attack of the game.