Jamie Cureton's 15th goal of the season earned his side the three points at Spotland this afternoon.
The 35-year-old scored the only goal when the sides met at The Park in October and he repeated the trick on the half hour mark after beating Owain Fon Williams to Richard Logan's flick on.
Logan's effort skimmed the bar shortly after but that's the closest either team came and City could reflect on a second clean sheet in five days.
Paul Tisdale made one change from Tuesday's cracking victory over Bournemouth - David Noble came in with Richard Duffy dropping to the bench.
City set up in a 4-4-2 formation with almost a diamond in the middle of the park and one of that midfield had the first chance of the game after two minutes, Harley's right-footed free-kick curling just wide.
Liam Sercombe has scored three times since December and he had a fantastic chance to score the game's opening goal on five minutes. Cureton span before rolling the ball to Sercombe on the right hand edge of the box, City's number 22 cut inside his marker but his shot was well saved by Rochdale's Welsh keeper.
Ben Hamer had little to do throughout though the Reading loanee had to be on his toes to smother Gary Jones' drive at the second attempt.
Matt Taylor then came close to meeting successive Harley corners before a thunderous volley from Noble dipped over the crossbar on 16 minutes.
Nine minutes later it was the home side's turn to threaten, Chris O'Grady's cross from the left hand flank was pushed towards the back post by Hamer but a combination of Troy and Scott Golbourne managed to keep the ball away from the lurking Liam Dickinson.
After Sercombe's stunning long range screamer flew past the post another chance fell to Dickinson when he rose to meet a corner but his header was just off target.
After an open half hour the opening goal came via a familiar source. The Logan/Cureton partnership was responsible for both goals on Tuesday and they carried on where they left off here. A long ball was knocked down by Logan into the perfect space between the defence and Fon Williams and Cureton was onto it in a flash. Sprinting onto the ball City's top scorer clipped the ball past the keeper and could watch it roll into the back of the net.
It was a typical striker's finish and showed the importance of being sharp and gambling around the box.
Logan then came very close to scoring his second of the week on 39 minutes. The overlapping Steve Tully had Fon Williams sprawling with a low daisy-cutter from the right hand side and the ball fell to Logan whose smashed effort clipped the crossbar on it's way over the bar.
The final chance of the half came when Sercombe weaved his way through but his low left-footed shot was into the keeper's midriff.
O'Grady had the first chance of the second 45 when he span and shot on the turn but his effort was kept out by a smart Hamer save at his near post.
Harley came very close to one of the goals of the season against Bournemouth and he repeated the feet with a cheeky chip on 61 minutes. Hitting a ball first time on the left hand edge of the box his cross/shot was not far away from lobbing Fon Williams and finding the top corner. What a goal that would have been.
Cureton then had two penalty appeals in quick succession waved away and shortly afterwards a perfect left-footed cross from Golbourne into the box was headed behind for a corner.
The chances may have dried up in the second half but this was down in part to some great blocks by Matt Taylor in particular. Tisdale sent on Duffy and O'Flynn and both played their parts superbly in the final minutes. The Irishman was praised by his boss after the game for the hold up play and hard work during his brief cameo.
With ten minutes to go home fans begun to leave Spotland, surprising given the amount of dangerous crosses and corners they were putting into box during the dying minutes.
But City were not really tested and they played out the four minutes of added time to chalk up their tenth away victory of the season,&nbsp;seven more than the whole of last season!
Plenty of the squad made a point of coming over and clapping their loyal supporters at the final whistle and there were plenty of happy faces as the players and fans prepared for their long trip home.
Yeovil await next on Saturday after a rare midweek off!