The division-leading Bruins reached 30 wins for the season while Dallas lost for the seventh time in eight games.
The Stars and Bruins then combined for five goals in the final period, an offensive show that started with Erik Cole tying the game for Dallas 1:18 into the stanza.
Brad Marchand put Boston back in front and Lucic came through on the power play with 4:14 to play.
Chad Johnson gave up two goals on 32 shots while Lehtonen made 37 saves in the loss.
Susan Sarandon 'very excited' about daughter's pregnancy
Senate Democrats to pull all-nighter on climate change