Darlington dropped regular keeper Andy Collett to the bench and gave reserve keeper Chris Porter only his fourth start of the season and the Quakers man was rarely troubled throughout the 90 minutes as Hull seemed happy to clinch a share of the points.
But Darlington's top scorer Barry Conlon had different ideas and the striker inspired his side to victory with a sparkling second-half performance.
The opening 45 minutes were easily forgettable as both keepers were rarely troubled and both side’s strikers could only muster speculative long-range efforts towards goal.
However, the second half began brightly and the toothless Tigers almost grabbed the lead in the opening seconds when Ben Burgess burst through and was only denied by a brave save from Porter.
Darlington settled down to take the lead in the 55th minute when an excellent crossfield pass from Conlon found on-loan defender Tom Newey on the edge of the Hull area.
The on-loan Leeds man burst forward before unleashing an unstoppable shot that gave Hull keeper Alan Fettis no chance.
The home side began to dominate and a Newey corner found the head of James Corbett who headed narrowly over the crossbar in the 67th minute and then two minutes later Corbett was again off target with an attempted lob over the stranded Hull keeper.
In the 75th minute Darlington should have doubled their advantage but midfielder Gary Pearson fired wide from inside the area. Hull were poor and Porter was on course to keep his first clean sheet of the season.
Ten minutes from time Ryan Valentine failed in an attempt to lob Fettis, but Conlon grabbed his 17th goal of the season in the dying seconds with a right-foot drive that bounced down off the crossbar and over the goal line.