A win on Friday night would have seen the Foxes edge into the top six ahead of Saturday's fixtures, and it looked like Pearson's men were going to end their eight-game winless run after Jeff Schlupp had headed them back in front.
But Blues substitute Chris Burke, back after a three-game absence with an ankle injury, kept his cool to net a last-minute penalty to snatch a point for the visitors.
Curtis Davies' own goal saw Leicester take an early lead but Nikola Zigic equalised just after the hour mark.
Leicester play eighth-placed Bolton on Tuesday night followed by games with Crystal Palace, Watford and Nottingham Forest, sides who are currently fourth, third and fifth in the table respectively.
"We probably have to win all four of our remaining matches now. It's do-able," said Pearson. "We've got to win the next game, but then we've been saying that for a while now.
"We've created enough chances to win this game comfortably and really we should have won the game.
"After Brighton at the weekend, that's two games running now that we've conceded equalising goals late in the game and had to settle for a draw.
"It's difficult to swallow. The mistakes that we are making at the moment are costing us dearly."
- Sports & Recreation
- Jeff Schlupp