Darlington came through a difficult test against a strong Scunthorpe side and new caretaker boss Mick Tait was delighted with his side's performance.
The visitors took an early lead after a mistake by defender Matthew Clarke let in former Darlington striker Martin Carruthers. The United front man strode forward in the fourth minute to blast the ball past Andy Collett in the home goal.
From that moment on Tait's side dominated the game and they were unlucky not to get on to level terms in the seventh minute. Richard Hodgson's corner was met by the head of Barry Conlon, but the striker's efforts blazed over the cross bar from a good position.
The home side went close again in the 12th minute when a Clark Keltie free kick was fumbled by Scunthorpe keeper Tom Evans but Conlon's follow-up failed to find the target.
In the 17th minute Scunthorpe roared back into the game and almost doubled their lead. Spaniard Alex Calvo-Garcia fired goalwards but saw his shot bounce off Darlington captain Craig Liddle.
In the 27th minute Darlington brought themselves level after Stuart Balmer brought down Conlon in the area. Ian Clark stepped forward to rifle in the equaliser from the spot.
The home side found themselves on the back foot at the beginning of the second half and Collett pulled off a superb save to deny United defender Andy Dawson, and as the visitors continued to force the pace Collett again came to his side's rescue to deny Carruthers.
In the 53rd minute Clark spotted Tom Evans off his line and he went close to putting his side in front with a cheeky lob that landed on top of the goal.
Five minutes of added time was signalled at the end and at the death Balmer was red carded by referee Mike Ryan for foul and abusive language