Tom Bradshaw came off the bench to score his fourth goal in four days and earn play-off chasing Millwall a vital point against runaway leaders Burnley.
The striker, who scored a hat-trick against Sheffield United on Saturday, snapped up a rare Lions chance to equalise with five minutes to go.
Ashley Barnes, who scored at Luton at the weekend, seemed to have bagged Burnley's winner for the second game in succession when he fired home after Scott Twine's shot had been charged down by Jamie Shackleton on 51 minutes.
The draw still meant the Clarets have a 12-point lead over second-placed Sheffield United as they seek to bounce back into the Premier League at the first time of asking.