Ian Henderson’s second half strike, which marked his 21st goal of the season, was the only goal of the game in the 1-0 victory.
It means Dale are still in with a chance of clinching a top six finish with two games of the season remaining.
Manager Keith Hill named five changes to the side which suffered a narrow defeat away at Gillingham in their last outing. After receiving red cards at the weekend, Jamie Jones and Matty Lund missed out through suspension. Joe Rafferty, Calvin Andrew and Reuben Noble-Lazarus dropped to the bench, while Josh Lillis, Rhys Bennett, Olly Lancashire, Scott Tanser and Michael Rose were all handed starts.
Both sides created early chances, with the first falling the way of the visitors. Ryan Hedges clipped a ball over the Dale defence to find Bartley in the box but after getting the ball under control, his pass across goal was tame and Lillis was alert to smother the ball at his near post.
Dale came within inches of opening the scoring after ten minutes but Henderson couldn't quite stretch far enough. Rose delivered a superb cross-field ball to find Vincenti in space on the right who slid a first time ball across the six yard line into Henderson's path. At full stretch however, he couldn't get his toe on the ball to poke it towards goal.
After a game of pinball inside the box, a chance eventually dropped to Jamie Allen twelve yards out. Andy Cannon and Henderson worked the ball patiently between themselves on the right wing before the latter clipped a cross to the far post. As Orient failed to clear their lines, the ball fell to Allen and he volleyed towards goal but he couldn't drive it through through the mass of red shirts in front of him.
HALF TIME: Rochdale 0-0 Leyton Orient
Alex Cisak had to show great awareness to keep Nathan Clarke from putting through his own goal from a deep Rose free kick. As the ball was floated into the box, the Orient captain completely miscued his header and with the ball looping into the top corner, Cisak got across well to tip the ball over the bar and save his team mate's blushes.
With 65 minutes played Rochdale took a deserved lead as Ian Henderson rounded off a flowing move. Rhys Bennett drove powerfully through the midfield before sliding the ball to Vincenti on the right. He had time to look up before picking out Henderson on the penalty spot who lashed the ball into the top corner of the goal.
A fantastic chance fell for Jamie Allen to double Dale's advantage after he was played through by Vincenti. Having driven through midfield, Vincenti poked the ball beyond the last defender, entering Allen into a foot race with Cisak. He won the race but could only poke the ball wide of the goal with Cisak sprawling at his feet.
A fantastic double save from the Orient goalkeeper kept Dale's lead to one as he denied Calvin Andrew. Rhys Bennett played Henderson through on goal but Cisak got down well to block his effort. It squirmed away to Andrew who appeared to have an empty net to slot into, but out of nowhere Cisak desperately flung himself at the ball to push it around the post.
From the resulting corner, Henderson stooped in at the near post to flick the ball on and over Cisak, but again the goalkeeper stretched out an arm to push it away. He didn't get enough his clearance to send it over the crossbar, however, as the ball looped towards the goal, his defender was on hand to hook the ball off the line and away from danger.
FULL TIME: Rochdale 1-0 Leyton Orient
Dale are back in action at Spotland on Saturday afternoon (3pm) – MK Dons are the visitors for the League One fixture.