Gary Mackay-Steven went down after a trip from Paul Hanlon - with the incident seemingly outside the box - but Russell made no mistake with the spot-kick.
A brilliant individual goal from Leigh Griffiths had earlier looked to have given the visitors the points.
The striker capped a man-of-the-match performance with his 18th strike of the season, although on the balance of play a draw was probably a fair result.
Former Hibs star John Rankin gave United the lead after just six minutes following a dreadful mistake by Ben Williams.
The keeper was too casual in coming to collect a back-pass and kicked the ball straight at Rankin, only to see it ricochet off the midfielder and into the back of the net.
Hibs gradually came back into the game, with Griffiths twice going close before another lapse of concentration at the back almost led to Mackay-Steven extending the home side's lead.
Stuart Armstrong then saw his pile-driver fly just over for the Tangerines, but it was Hibs who got the all-important second goal.
Griffiths curled in a free-kick from the edge of the box and James McPake rose to power home a header past Radoslaw Cierzniak.
Five minutes into the second half the game turned on its head after an outstanding individual goal from Griffiths.
The striker, who also hit the woodwork before the break, picked up the ball in his own half, left Rankin for dead and unleashed a 20-yard rocket which had Cierzniak grasping thin air.
United pressed for an equaliser, with Rankin smashing a 20-yarder just over, while Williams did well to tip over Armstrong's header.
In a frenetic finish, Rankin blasted just over from distance before the award of the penalty five minutes from time which was gratefully smashed home by Russell.