Substitute Magaye Gueye struck an equaliser in the fifth minute of injury time as Millwall snatched a 1-1 draw at Sheffield Wednesday.
The winger fired his first Lions goal into the roof of Keiren Westwood's net with virtually the last kick of the game at Hillsborough.
Millwall looked to have squandered their chance to grab a share of the spoils when Shaun Williams missed an 85th-minute penalty after Chris Maguire put the Owls ahead with a free-kick early in the second half.
Both sides were unbeaten and yet to concede a goal going into the game following two league games and one in the Capital One Cup, with the Lions having recorded successive victories.
The away side enjoyed the majority of possession in the opening stages and they threatened first when winger Lee Martin curled a 25-yard free-kick wide of Westwood's goal in the 13th minute.
The home side responded and striker Atdhe Nuhiu nodded a Maguire corner narrowly over the crossbar from close range before central defender Tom Lees headed straight at Lions goalkeeper David Forde from another corner, this time taken by wideman Jacques Maghoma.
Millwall winger Martyn Woolford had the visitors' most presentable chance of the first half in the 37th minute but, after finding space just inside the Wednesday 18-yard box, he placed his looped effort off target.
The Owls then had an excellent opportunity of their own following a mistake by Forde. Maghoma seized on the keeper's poor clearance and raced into the area but, instead of shooting first time, he opted to cut inside before going to ground and seeing his penalty appeals waved away by referee Nigel Miller.
The second half began in scrappy fashion with both sides struggling to carve out a meaningful chance in front of goal before Maguire broke the deadlock 12 minutes after the restart.
Martin was penalised for handball on the left-hand edge of his penalty area and Maguire took full advantage, driving a low free-kick through the Millwall wall and into the bottom right corner for his first goal of the season.
Lions boss Ian Holloway reacted immediately to the setback, introducing attacking duo Ricardo Fuller and Gueye and the two combined minutes later before the latter's powerful attempt was blocked behind for a corner.
Woolford was the next to threaten an equaliser when his left-footed shot from range flew narrowly past the top left corner with Westwood at full stretch.
Maguire went close to doubling his tally 13 minutes from time when his left-footed drive from distance fizzed over Forde's crossbar after he was teed up by substitute Gary Madine.
Millwall were given the perfect opportunity to grab a share of the spoils five minutes from time when referee Miller pointed to the spot after a coming together between Martin and Westwood.
Williams, who had been successful from the spot in the Lions' opening day win over Leeds, stepped up but his low effort hit the right-hand upright before French winger Gueye spared his blushes at the death.