Match ends, Sheffield Wednesday 1, Millwall 1.
Substitute Magaye Gueye's injury-time goal preserved Millwall's unbeaten record against Sheffield Wednesday.
Wednesday led through a Chris Maguire free-kick after 57 minutes on his 50th appearance for the club.
Millwall missed a penalty through Shaun Williams but rescued a point when Gueye, 24, fired home.
It was the former Everton winger's first goal since signing for Millwall in the summer and kept Ian Holloway's side level at the top of the table.
The Owls had also enjoyed an unbeaten start and threatened from a couple of first-half corners with striker Atdhe Nuhiu heading over and defender Tom Lees nodding straight at goalkeeper David Forde.
Wednesday's Jacques Maghoma should have made more of an error from Forde when he seized on a poor clearance but failed to shoot, while Martyn Woolford had Millwall's best chance of the first half which he put wide.
Neither side was able to dominate but 12 minutes into the second half Lee Martin was penalised for handball and Maguire drove the free-kick through Millwall's wall to put the home side ahead.
Lions' boss Ian Holloway sent on Gueye and Ricardo Fuller to liven up his attack and Woolford almost levelled with a shot which went just over the top.
But when Williams then missed from the spot, shooting against a post after goalkeeper Keiren Westwood had fouled Martin, it looked as though Millwall's impressive start would suffer its first setback until Fuller teed up Gueye to shoot into the roof of the net.
Sheffield Wednesday manager Stuart Gray: "Sometimes you've got to take pride in the result. I didn't get the performance that I was after but I just felt when we got our noses in front we looked more likely to be the side to get the next goal.
"I just said to the players, we're going to have massive highs and massive lows and at the moment the dressing room is very, very low because it feels like a defeat.
"It's the last 10 seconds of the game where we've conceded, but it just shows that's why we all love football so much; it keeps you on the edge of your seat and you never know what's going to happen."
Millwall manager Ian Holloway: "I thought we got lots of things wrong in the first half; we over-played, we over-passed, we forgot to go and try and create anything against a very good team.
"I thought it was a very tough game for us. In the second half we got a little bit better.
"I was so proud of my boys to not only get over the disappointment of missing a penalty but to still have enough skill and prowess to create a wonderful goal and score it. I'm delighted because it feels like we've won a game."
- 1WestwoodBooked at 84mins
- 5LoovensBooked at 90mins
- 4HutchinsonSubstituted forCokeat 66'minutes
- 19MaghomaSubstituted forHelanat 79'minutes
- 9NuhiuSubstituted forMadineat 71'minutes
- 26AbdouSubstituted forGueyeat 60'minutes
- 7MartinSubstituted forEasterat 90'minutes
- 9GregorySubstituted forFullerat 60'minutesBooked at 90mins
- Nigel Miller
- Shots on Target
Second Half ends, Sheffield Wednesday 1, Millwall 1.
Goal! Sheffield Wednesday 1, Millwall 1. Magaye Gueye (Millwall) right footed shot from the centre of the box to the high centre of the goal. Assisted by Ricardo Fuller.
Foul by Magaye Gueye (Millwall).
Josè Semedo (Sheffield Wednesday) wins a free kick in the defensive half.
Scott McDonald (Millwall) wins a free kick in the attacking half.
Foul by Chris Maguire (Sheffield Wednesday).
Attempt blocked. Ricardo Fuller (Millwall) right footed shot from outside the box is blocked. Assisted by Magaye Gueye.
Ricardo Fuller (Millwall) is shown the yellow card.
Glenn Loovens (Sheffield Wednesday) is shown the yellow card.
Attempt missed. Scott Malone (Millwall) left footed shot from outside the box is high and wide to the left.
Attempt blocked. Carlos Edwards (Millwall) right footed shot from the right side of the box is blocked. Assisted by Jermaine Easter.
Attempt missed. Stevie May (Sheffield Wednesday) right footed shot from outside the box misses to the left.
Substitution, Millwall. Jermaine Easter replaces Lee Martin.
Corner, Millwall. Conceded by Glenn Loovens.
Magaye Gueye (Millwall) wins a free kick in the defensive half.
Dangerous play by Josè Semedo (Sheffield Wednesday).
Corner, Sheffield Wednesday. Conceded by Martyn Woolford.
Corner, Sheffield Wednesday. Conceded by David Forde.
Attempt saved. Ricardo Fuller (Millwall) header from the centre of the box is saved in the top centre of the goal. Assisted by Scott Malone with a cross.