There was no happy return for former O's manager Tommy Taylor as he saw Leyton Orient come from behind to record their first win in eight games.
Darlington had grabbed the lead on the stroke of half time and striker Barry Conlon headed home, but second-half strikes from Carl Hutchings and Kevin Nugent saw Orient end their barren run.
After the game disappointed Darlington boss Taylor admitted: "We were quite comfortable in the first half and I thought we had kept Orient quiet, but in the second half Campbell-Ryce opened us up down the wing and caused us all sorts of problems."
Meanwhile a delighted Orient boss Paul Brush said: "I'm hoping this will be a major turning point for us. We have shown we can come from behind and win a game."
The O's boss added: "We put in some good quality crosses in the second half and I thought we deserved it but it was still a relief to hear the final whistle."
The Orient manager also had a word of praise for goal hero Nugent: "I thought he was playing well before he scored. He won lots of balls in the air.
"He has got experience and knowledge and gives everything he's got and that's what we needed."
Orient started well and Nugent saw an early effort well saved by Darlington keeper Andy Collett.
But the visitors weathered the early storm and had chances themselves when David McGurk headed just wide and then Conlon tested Glenn Morris with a speculative 25-yard drive.
Although Darlington had to reorganise when they lost Matthew Clarke after 33 minutes they took the lead in first half stoppage time when Conlon rose high at the far post to head home Neil Wainwright's right-wing cross.
Orient levelled on the hour when Hutchings netted his first of the season after Collett had parried his first shot and then Nugent wrapped things up with a diving header 17 minutes from time following a cross by Jamal Campbell-Ryce