Lizotte scored 1:09 later to tie it 1-1, knocking in a loose puck near the crease after Olli Maatta's centering pass was blocked by David Pastrnak.
Smith put Boston back in front 2-1 at 19:05 of the second period with a wrist shot over Petersen's blocker from the low slot off a pass from Coyle.
"It's tough. I thought for the most part we did a lot of good things," Smith said. "There's only two things you can do, you can sit and be [mad] about it, which we are right now, but we've got to make the next step forward, make the corrections and make sure that we're tightening up. It's all things we can fix, and we have the people to do it."
NOTES:Athanasiou has scored three goals in his past two games after being a healthy scratch in the previous five. … Kings defenseman Mikey Anderson left the game with an upper-body injury. Anderson went to the locker room after a collision with Bruins forward Brad Marchand at 10:36 of the first, and although he returned for the end of the period, he did not play in the second or third. … Los Angeles has 71 points in 58 games this season. It is the fifth-fewest games needed to reach the mark in its history, behind 1974-75 (50 games), 1980-81 (54), 2009-10 (56) and 2015-16 (57). … Smith has scored five goals in his past three games.