Nathan Smith’s second half header, which took a deflection, separated the two sides.
There was one change to the side that lined-up against Sheffield United on Saturday, as Joe Rafferty missed out through injury. Scott Tanser came into the starting eleven, while Matty Lund returned from injury to take a place on the bench.
After a lively opening period, Dale had the first sights on goal.
In the ninth minute, Nathaniel Mendez-Laing forced Jak Alnwick into a save after striking an effort from the edge of the area. The Valiants ‘keeper dived to his right to keep him out.
Five minutes later, McDermott unleashed an effort from 25-yards straight at Alnwick, who got down low to collect.
Vale’s Anthony Grant could thank himself lucky to stay on the pitch after committing two cynical challenges during a three minute spell. He went in the book after scything down Ian Henderson as Dale hit the Valiants on the break, but he went unpunished for a foul on Jamie Allen a few minutes later.
Andrew was next to get a shot on target, as he struck goal-wards after a fine passage of play by Dale. He wasn’t able to get enough power behind the effort, though, and Alnwick comfortably kept him out.
But it was Port Vale’s Anton Forrester who squandered the best chance of the half so far shortly before the half hour mark. He raced onto a delivery across the face of goal and somehow headed wide of the target from six-yards.
In the final moments of the half, Dale also had an opportunity to take the lead. After a quick move forward, Mendez-Laing looked to shoot but instead played in Henderson, who poked wide from close range.
HT: PORT VALE 0-0 ROCHDALE
Seven minutes after the re-start the home side opened the scoring through Nathan Smith. After getting on the end of a set-piece, his header took a wicked deflection, sending it over the outstretching Lillis.
GOAL: Port Vale 1-0 Rochdale (Smith, 52 minutes)
Rochdale substitutions soon followed as Callum Camps firstly replaced Scott Tanser. McDermott then made way for Sanmi Odelusi a short time later, before Joe Thompson was introduced in place of Andy Cannon.
Clear cut opportunities were at a premium as the half continued.
But in the closing stages of the game the home side ramped up the pressure and had the opportunity to extend their lead after being awarded a penalty four minutes from time. JJ Hooper stepped up to take the spot-kick and hit wide of the target.
A couple of minutes later, Allen came close to finding Dale’s equaliser. He picked up a loose ball and fired a dipping effort just over the bar.
In stoppage time, a last gasp block by Harrison McGahey prevented Alex Jones getting a shot away after he’d charged in on goal and rounded Lillis.
Dale hit the Valiants on the break and Nathaniel Mendez-Laing’s shot-come-cross, which was sent across the face of goal, was saved by Alnwick, in a pulsating end to the game at Vale Park.
FT: Port Vale 1-0 Rochdale