Rovers were caught late as ten-man Millwall came from two goals down to claim a share of the spoils on a dramatic evening at the Den.
The visitors seemed in control after a first goal for Rovers from Shane Duffy in the first half was followed up by yet another for Rudy Gestede in the second.
However the home side brushed aside the disappointment from losing Andy Wilkinson to a straight red card to score two dramatic late goals.
Lee Martin gave the Lions hope on 72 minutes before Shaun Williams completed the comeback in the 88th minute to deny Rovers a fourth straight victory.
Rovers spurned late chances to grab a winner in seven added minutes, but whilst they stretch their unbeaten run to six, they should have been celebrating it with all three points.
Ahead of the game, Rovers made just the one change from the side that defeated Reading at Ewood on Saturday. Lee Williamson picked up a groin strain in the 3-1 win, his place taken by Ryan Tunnicliffe.
For the hosts, they made two changes from the side that lost at Watford at the weekend. With central defensive pairing Danny Shittu and Mark Beevers returning, Alan Dunne and Byron Webster both dropping to the bench.
It was Rovers with the early momentum at a drizzly Den. A flowing move saw Alex Baptiste shoot into the side-netting on six minutes, before Tom Cairney fired high over the bar after Ben Marshall had out-muscled the imposing figure of Danny Shittu.
A swift break at the midway point of the half very nearly saw Rovers take the lead. As Marshall fed Markus Olsson out wide the Swede delivered a great ball into the box for Jordan Rhodes, however, the striker couldn't get his header on target.
As the half wore on the home side grew into the game. Matthew Briggs fired over after a spell of Millwall pressure, before Shaun Williams tested Jason Steele with a 35-yard strike. the Rovers goalkeeper taking no chances in tipping the effort over the bar.
It was a scrappy first half with little quality on show, but Rovers weren't too bothered as they grabbed the lead on 37 minutes, albeit in a scruffy fashion in keeping with the game.
After Rudy Gestede had been fouled by Shittu, Marshall delivered into the box, Shane Duffy stuck out a boot but his first effort was blocked, however the Irishman was alert to poke the rebound into the back of the net.
It was Duffy's first goal in Rovers colours since his move from Everton at the end of August.
As the home side looked for a way back before the break it was Rovers who should have doubled their advantage. A swift counter saw Marshall and Rhodes combine before the ball was played to Cairney on the edge of the area but his curling shot flashed inches the wrong side of the post.
The rain showed no signs of abating as Rovers got the second half underway, neither side making a change at the break.
No doubt with their manager's half-time talk ringing in their ears, Millwall came out with much more purpose at the start of the second half.
On an increasingly tricky surface, the Lions twice tried long-range strikes. Williams following up his first half effort with a shot along the ground which Steele claimed comfortably, fellow midfielder Ed Upson was wayward with his attempt.
The home side upped the pressure with Rovers throwing bodies on the line to keep their lead, Ryan Tunnicliffe superbly blocking a Lee Martin shot, Alex Baptiste thwarting Fuller from the resulting corner.
The match was bubbling nicely but on 61 minutes the game erupted when Millwall full back Andy Wilkinson was shown a straight red for a late challenge on Ben Marshall.
Remonstrations followed and it was fully four minutes before play resumed and with it Rovers doubled their advantage.
Alan Dunne, on for defensive reinforcement, clumsily brought down Jordan Rhodes in his first involvement in the match, Tom Cairney sent the resulting free-kick into the area and Rudy Gestede nodded into the corner for his ninth of the campaign.
But their two-goal advantage only lasted seven minutes as the home side grabbed a goal their endeavour deserved.
Ricardo Fuller, so hard to knock off the ball, fed Lee Martin and the Millwall man slammed the ball into the corner of the net.
Millwall were throwing everything at Rovers, but just as it looked like they had weathered the storm, both on and off the pitch, the Lions levelled with two of the 90 remaining.
Shaun Williams had twice tested Rovers with long-range efforts, but his third would find the target. A sumptuous strike that flew into the bottom corner giving Steele no chance.
Rovers almost responded straight away as Tom Cairney bundled his way into the area, but Corry Evans fired over the bar.
There was gasps around the Den as seven additional minutes were shown, a seven minutes that Rovers dominated but couldn't grab a late winner.
Ryan Tunnicliffe fired over before Rudy Gestede twice spurned late chances, heading over an Evans centre, before lashing another over the bar from close-range.
The two sets of players went off to the strains of "Crazy Crazy Night", it most certainly was.
MILLWALL: Forde; Wilkinson, Shittu (c), Beevers, Briggs; Williams; Upson (sub Gregory 60 mins), McDonald (sub Dunne 64 mins); Martin, Fuller (sub Gueye 74 mins), Woolford.
Subs not used: King (GK), Webster, Chaplow, Ranegie.
Goals: Martin 72 mins, Williams 88 mins,.
Booked: Fuller, Williams.
ROVERS: Steele; Baptiste, Hanley (c), Duffy, Olsson; Cairney, Evans, Tunnicliffe, Marshall (sub Conway 81 mins); Gestede, Rhodes (sub Varney 87 mins).
Subs not used: Eastwood (GK), Henley, Kilgallon, Dunn, Taylor.
Goals: Duffy 37 mins, Gestede 65 mins.
Attendance: 8250 (including 486 Rovers fans).