An astonishing first-half display earned Dundee, the Dee a first derby victory over neighbours Dundee United at Tannadice since 2004 and eased their Scottish Premiership relegation fears.
A bullet header from Jordan McGhee opened the scoring for the visitors and Scott Tiffoney doubled their advantage soon after, as his shot from long range squirmed horribly out of goalkeeper Jack Walton’s grasp.
Glenn Middleton’s curling left-footed strike halved the deficit for United, but McGhee whipped home his second before half-time to restore Dundee’s two-goal cushion as their hapless hosts struggled to contain them.
The Dee could have led by more at the interval – two goals were chalked off for very narrow offside calls and Simon Murray fired inches wide on the turn after United failed to clear a corner.
However, having been comprehensively outplayed in the opening 45 minutes, United brought themselves back into the contest after the break as Kristijan Trapanovski’s deflected effort nestled in the net.
Both sides had chances from there. Joe Shaughnessy’s header bounced just over for Dundee, while Sam Dalby could not steer his own headed effort on target.
But as United threw on a succession of attackers in search of a leveller, Dundee struck the telling blow late on.
Substitute Emmanuel Adegboyega – by then United’s sole defender – was shown a second yellow card for desperately shoving Murray in the box.
The Dundee fan picked himself up to seal the win from the spot before gleefully running the length of the Tannadice pitch to celebrate in front of the United fans.
It is Dundee’s first league win since 5 January and their first top-flight victory at Tannadice since a 2-1 triumph under Jim Duffy in August 2004.
Tony Docherty’s side move to within one point of Kilmarnock in 10th and are five clear of bottom side St Johnstone.
United, meanwhile, stay fifth, three points ahead of seventh-placed Motherwell with three games left before the split.
