Colchester United have lost at Exeter City as the visitors took hold of the game in the second half.
The Grecians opened the scoring a minute before half time, as Matt Jay volleyed home after the ball fell to him on the edge of the box.
With the U's chasing the game in the second half, the hosts extended their lead through Lee Holmes and Nicky Law.
Mikael Mandron controlled a ball in the box on six minutes, but his subsequent shot didn’t have any power behind it, and Pym comfortably took it in at the near post.
At the other end, the first Exeter effort came on eighteen minutes, but Hiram Boateng’s volley was high and wide.
Dean Moxey had to make a last ditch block to prevent Courtney Senior’s shot testing Pym in the twenty fourth minute, before Ryan Bowman’s acrobatic overhead kick flew just over the U’s bar.
The Exeter forward turned provider a minute before half time, as the hosts took the lead.
He challenged Luke Prosser in the air on the edge of the U’s box, and the ball bounced down to Matt Jay.
Jay didn’t break stride and volleyed his effort gave Gilmartin no chance as the shot went past his right hand and into the far corner of the net.
That was the final goalmouth action before the half time whistle went, and the U’s went in for the break a goal behind.
They should have been level a minute after the break, but Szmodics’ shot was saved by Pym when the U’s top scorer was clean through.
Mandron then had a shot blocked after good work from Ryan Jackson and Luke Norris and the U’s had started the second half well.
Whilst the U’s were looking to get forward at every opportunity, they were conceding chances at the other end.
Gilmartin had to make a smart save with his legs to deny Holmes, and then saw Bowman hit a shot narrowly wide from a tight angle.
And the lead was doubled on sixty six minutes when Holmes latched onto a ball forward, and cleverly dinked the ball over Gilmartin and to make it 2-0.
That goal spurred the U’s on, and Frankie Kent was next to try his luck but headed over.
It looked like the U’s had got one back on sixty nine minutes, but Pym dived full length to fingertip a Mandron drive away for a corner.
The home keeper then produced another fine save from the resultant set piece, this time to push away a curling Szmodics’ effort.
Mandron then shot wide as the U’s continued to dominate, but they were caught by a sucker punch with fourteen minutes remaining.
Boateng got the better of the U’s midfield, then timed his pass to Nicky Laws perfectly for a poked finish past Gilmartin from ten yards out.
It could have got worse for the U’s in the final minutes, but Gilmartin tipped a strike from Kane Wilson away for a corner.
With five minutes to go, Todd Miller became the youngest U’s player to appear in a first team fixture – at 16 years and 166 days.
He was denied a debut goal three minutes after coming on, being flagged offside as he raced onto a diagonal ball from the left.
The hosts comfortably saw out the added time, and the U’s slipped out of the Play-Off places after the third 3-0 reverse in four matches.
They face another of their rivals for promotion next weekend, with Tranmere Rovers visiting the JobServe Community Stadium.