It certainly wasn't an afternoon for the defences as the Northern Counties League side raced into a 4-2 lead but Eric Kinder's side turned it around with three goals in the final five minutes to snatch victory at the death.
After a bright opening from Rovers it was the home side who took the lead on 19 minutes, Colin Heath applying the finishing touch from close range after Rovers were caught out at the back.
But they were soon back on level terms as Hyuga Tanner rose well to meet Jack Doyle's cross to head home on 33.
Former Manchester United youngster Heath then grabbed a quick-fire double to claim a first half hat-trick to put Knaresborough in control at the break.
Like the first half, Rovers started the second strongly, this time getting a goal their improved play deserved, second half substitute Sam Lavelle nodding home from close range on 70 minutes to reduce the scoreline to 3-2.
However it was soon 4-2 as Tom Robinson turned the ball home from inside the area.
Eric Kinder's side looked to be heading towards a second successive pre-season defeat, but amazingly they scored three goals in the final five minutes to turn the game on it's head.
Jordan Slew made it 4-3 on 85, following up after his initial shot had been well saved, before Jordan Preston equalised a minute from time.
There was still time for Rovers to grab a fifth and winning goal, Slew advancing well before curling his effort beyond the Knaresborough goalkeeper.
Rovers' Under-21s are back in action this Tuesday night when they face AFC Darwen at the Anchor Ground. Kick-off is 7.45pm. Admission prices are Adults £7, OAP's £3 & Children £1.