The Lions sit ninth in the Championship table, with Burnley leapfrogging their opponents and underlining their promotion credentials with a goal in each half at The Den, Sam Vokes and Danny Ings on target.
A disappointed Jackett said: "The result didn't please me. We didn't do enough to get something out of the game. Burnley showed more hunger and desire for the game than we did and that's disappointing," said Jackett.
"We started the game poorly, on the wings they got in behind and got off crosses far too easily. The first goal is a prime example. He (Junior Stanislas) went past two to deliver for Sam Vokes to score.
"We didn't defend well, not with everything we've got, not for our life, which we do when we're playing well.
"Going forward, take the start of the second half, we spread the ball across the face of goal but didn't get on the end of it.
"We needed that goal to go and lift us and lift us again. We changed formation in the last half hour to free up the centre but we couldn't do enough.
"Burnley were in defensive mode by then, they had the lead and we couldn't move the ball well enough to get in behind them."