Liverpool have now drawn three of their last four Premier League games, and captain Henderson believes that the decision in the meeting with the Potters cost his side three points.
"In the second half we created enough to win the game. We should have won it comfortably," Reds captain Henderson told Sky Sports News.
"It looked like a clear penalty in play and I've just looked back on the tele and it's blatant. If he doesn't touch it with his hand it's a goal.
"It's a really poor decision from the referee and linesman, it's cost us three points."
Liverpool have missed out on the chance to go second in the league table but move four points clear of Tottenham Hotspur in fourth.