Huddersfield survived two Millwall penalty appeals in a goalless League One play-off semi-final first leg at the Galpharm Stadium.
Scott Barron's first-half shot appeared to strike the raised hand of Town defender and skipper Peter Clarke.
And Clarke was involved again after the break when a trip on Barron went unpunished.
Lee Clark's side scored 82 league goals on their way to securing sixth place, but failed to find the net on home soil when it mattered for the first time since January 19.
Lee Clark: "I think it is very evenly balanced. You have seen some very committed players from both teams.
"It could go either way on Tuesday. Just because it is a draw on our home patch counts for nothing, and I think Kenny (Jackett) will know that as well.
"It was very tight. My players have put a magnificent effort in and we played some great football.
"We just lacked a little bit of conviction maybe in the penalty area, but we created some decent openings and it is all set up for Tuesday evening now."
Police were forced to break up "ugly" scenes between fans as three supporters were arrested after trouble flared in the stands following the final whistle at the Galpharm Stadium.
Officers with batons entered the visiting fans' section of the ground as bottles were thrown on to the pitch and between the two sets of supporters.
One Millwall fan was taken from the stand with what appeared to be blood on his face.
A spectator, who did not want to be named, said: "It kicked off in the Millwall end behind the goal. They started lobbing bottles and things and they all rushed to the bottom corner, where the Huddersfield fans were.
"The Huddersfield fans were also throwing stuff back at them and it all got a bit ugly.
"The police stopped it fairly swiftly by forming a cordon and pushing the Millwall fans back up the stand."
The two teams will play the second leg at the New Den on Tuesday night.