Joe Ironside rescued Rovers from the penalty spot to snatch a last gasp point at Sutton United.
Rovers had struggled to make a significant impression for much of the afternoon and looked to be heading for a defeat after Craig Eastmond put Sutton in front.
But there was to be a dramatic finish as Ironside was clattered into by Sutton keeper Dean Bounzanis, deep into time added on, and the striker showed tremendous composure to fire home from 12 yards.
The hosts arguably had the edge in a scrappy affair that lacked a good degree of quality throughout.
But Rovers struck when it really counted to earn a hugely valuable point in the capital.
Goalkeeper Thimothée Lo-Tutala made his debut as Grant McCann opted for six changes from the side that started against Stockport County in the league a week prior while Hakeeb Adelakun was handed his first start for the club. Captain Richard Wood, Jamie Sterry, Jack Senior and Billy Waters also came into the XI.
Rovers were straight on the front foot from the start and had a huge shout for a penalty when Waters went down under challenge from Bouzanis as he raced to meet a flick-on but found himself in the book for diving.
McCann’s side started the brighter and could not find the bounce of the ball during a scramble in the box after Owen Bailey saw a rasping drive blocked.
Jamie Sterry volleyed narrowly wide with the outside of his boot from the edge of the box in one of only a handful of half chances over the opening quarter of the game.
The hosts began to establish control of play and had Rovers on the back foot for much of the remainder of the first half. Lee Angol drew a first save from Lo-Tutala after hooking a volley on goal from 15 yards.
The Hull City was given more of a stern test just after the half hour mark as he got down low to bat away a shot from Olly Sanderson who was played clear in the box.
Rovers struggled for sustained possession as the half wore on but had another good chance when Waters latched onto a flick-on from Wood only to see his poked shot blocked out for a corner by Ben Goodliffe.
Waters volleyed over the bar from distance from 20 yards in the final action of the first half.
The early stages of the second half were a low key affair with both sides unable to get a grip on proceedings.
Rovers had another huge shout for a penalty as Senior was felled by Ryan Jackson as he raced into the box but referee Scott Simpson was unmoved.
Former Rovers loanee Charlie Lakin volleyed narrowly wide from the edge of the box as Sutton began to look the more threatening.
And they took the lead on 73 minutes. Jackson curled in a cross from the right and Eastmond turned the ball beyond Lo-Tutala to put Sutton ahead.
It was Sutton who looked the more likely to find the next goal as Omari Patrick twice missed the target from good positions.
There was a glorious opportunity for a Rovers equaliser when substitute George Broadbent clipped a cross into the middle and Ironside stabbed the ball over the bar under pressure.
It looked as though time had run out for Rovers as the five minutes of time added ticked by but in the dying seconds Bouzanis careered into Ironside and Simpson pointed to the spot.
Ironside showed incredible composure to fire home from the spot and earn Rovers an important share of the spoils.
Rovers: Lo-Tutala, Sterry (Taylor 75), Olowu, Wood, McGrath (Maxwell 46), Senior, Bailey, Rowe (Hurst 82), Adelakun (Broadbent 59), Waters (Molyneux 75), Ironside. Subs not used: Jones, Craig.