Sam Winnall scored hat-trick for Barnsley as Dale were beaten 6-1 at Oakwell.
Rochdale fell behind to an early headed goal from Alfie Mawson, before Winnall made it 2-0 shortly after the break.
Dale pulled one back through substitute Nathaniel Mendez-Laing, but Barnsley regained their two goal cushion thanks to a second from Winnall.
Then came a crazy finish to the game, as Marley Watkins made it four with a driven effort. Winnall secured the match ball with a free header into an empty net after Josh Lillis had come out to claim a high ball, before Kevin Long completed the scoring with a free header.
There was one change from the side that last at home to Chesterfield a fortnight ago, with Callum Camps returning in place of Jamie Allen who dropped to the bench. Joe Bunney returned to the squad, with Tom Kennedy missing out.
There was a very subdued atmosphere inside Oakwell, but a goal inside the opening ten minutes had the home fans on their feet. Adam Hammill swung a free-kick on from the left to which Mawson beat Josh Lillis, heading into the back of the empty net.
An early blow for Dale but the first half was even affair thereafter. Hammill saw a dipping volley fly over, whilst a clever throw from Michael Rose at the other end found Camps in the penalty area, but his cross-shot was cleared a yard from the goal line before Matty Lund’s follow up effort was blocked.
There was almost an embarrassing moment for Lillis as he slipped trying to close down a ball over the top, but Hammill, under pressure from Andy Cannon, could only send his lobbed effort well wide.
Barnsley stopper Adam Davies was tested by a stinging Camps drive from just outside the area, before Lillis had to make a simple stop from Sam Winnall after a nice move from the home side which involved a lovely back-heel from the lively Hammill.
Dale began the second half on the front foot, pressing the home side’s back line. That pressure led to a volley from Ian Henderson which was deflected into the arms of Davies.
However, just two minutes later the home side doubled their lead thanks to a swift counter attack. Hammill broke free down the left and played the ball across to Winnall, who turned the ball home at the near post.
Manager made a triple substitution on the hour mark. Calvin Andrew, Cannon and Donal McDermott made way for Bunney, Mendez-Laing and Allen.
The hosts were proving to be a threat on the counter as Dale pushed on. Winnall had a shot from a tight angle saved by Lillis, before the striker pulled a ball back for the onrushing Conor Hourihane, but the Barnsley skipper scuffed his shot wide.
They were let-offs for Dale who did get a goal back in the 65th minute through one of the substitutes. Michael Rose’s corner found the head of Mendez-Laing who glanced the ball home into the side netting.
The reduced deficit was short lived for Dale though, as Barnsley regained their two goal cushion four minutes later. Their break came down the right this time through substitute Ashley Fletcher, who squared the ball to Winnall for a simple finish.
That goal seemed to take wind out of the sails for the visitors who couldn’t create a clear cut opening as the game entered the closing stages.
Lillis was called into action when Fletcher broke the offside trap, closing the down the striker as he tried to lift the ball over him.
The home side did notch a fourth though with four minutes of the game to go. Fletcher beat a couple of Dale defenders on the edge of the area before finding Watkins free on the right side of the area. His shot hit Lillis on the way through to rippling the back of the net.
It was the first of three goals in less than eight minutes for the hosts, who made it five with a minute of normal time remaining. Lillis was beaten to a high ball which fell for Winnall to rise highest and nod into the empty goal for his hat-trick.
Former Dale loanee Long rubbed salt into the wounds in injury time as he turned home a free header after a cross from the left hand side, making it 6-1 at completing the scoring.