The Foxes lost more ground on the npower Championship's top two with Saturday's 1-0 loss at The Den, leaving them five points behind second-placed Crystal Palace and a further two points adrift of league leaders Cardiff.
"We are still well in the shake-up," said Pearson, whose team are fifth in the table.
"It is very tight above us. I have a good handle on the perspective.
"It was a missed opportunity against Millwall but we are in and amongst it."
Leicester host Cardiff at the weekend before a Boxing Day trip to fourth-placed Hull, Pearson's former club.
The Foxes boss added: "We have two games coming up and, if we beat them, we can make a big impact because they are teams around us in the table."