Johnny Russell blotted his copybook with a red card after his quickfire double helped Dundee Utd win the first competitive city derby in seven years.
Goalkeeper Radoslaw Cierzniak denied Nicky Riley as Dundee pressed early on, but a Rab Douglas mistake allowed Gavin Gunning to head in on 14 minutes.
Russell's deflected effort lifted over the Dundee goalkeeper after 35 minutes.
He fired in a stunner three minutes later but was sent off with Dundee's Stephen O'Donnell on 72 minutes.
That did nothing to temper the joy of most of a 14,000 capacity crowd at Tannadice that witnessed United go top of the Scottish Premier League with a game in hand.
That game is away to Celtic, but for now Peter Houston's side are the pacesetters and the most likely to mount a challenge to the reigning champions in the absence of financially ruined Rangers.
United, who beat Hibernian impressively in their opening SPL fixture, quickly applied pressure as they looked to recover from their 5-0 hammering by Dinamo Moscow in the Europa League qualifiers in front of a crowd that had the stadium - and the whole city - rocking.
The home side were without in-form winger Gary Mackay-Steven through injury, but only a desperate block on the edge of the penalty box prevented his replacement, Michael Gardyne, from finding the target with a powerful early drive.
Dundee manager Barry Smith had made one change and it was a conservative one, with Riley replacing striker Mark Stewart after the midfielder's return from injury.
However, Riley was quickly involved in the United penalty box and should have opened the scoring only to have two efforts parried by Cierzniak from point-blank range before the ball was scrambled for a corner.
That instilled some uncertainty in a United defence in which Sean Dillon was preferred to Brian McLean, but it was United who took the lead.
Jon Daly had scored a hat-trick in a pre-season friendly between the sides and the Dundee defence appeared to be concentrating on blunting the big striker as Willo Flood's free-kick was misjudged by Douglas and Gunning headed in at the back post.
United were catching Dundee on the break and, when Daly threaded in Russell, the former Scotland Under-21 striker's low drive took a deflection off the despairing Davide Grassi, flew over Douglas and spun into the far corner of the net.
Dundee will feel aggrieved about Russell's second, which immediately followed an incident at the other end for which they should have been awarded a penalty, Riley shoved by Richie Ryan on the edge of the penalty box.
Instead, a Ryan Conroy free-kick struck the defensive wall, Russell broke into the Dundee half and fired a blistering left-foot drive into the top corner of the net.
Douglas made some amends for his early flap after the break by pushing clear a powerful Ryan drive and then saving a downward Daly header on the goal-line after Flood followed up by floating a cross to the back post.
Cierzniak dived low to save a fine drive by Conroy, but the biggest talking point of a feisty second half was the double red card, with Russell perhaps unlucky to be dismissed for a half-hearted kick out at O'Donnell after the midfielder's late challenge.
While United are flying high, defeat leaves Dundee at the foot of the table looking for their first win - and first goal - back in the top flight.