The teams' previous four meetings had all gone to overtime or a shootout, including the Kings' 4-3 victory on Nov. 20 after they blew a 3-0 lead on the road.
Los Angeles has won two straight after going 3-13 in its previous 16 games, a plunge that dropped it from being one of the top teams in the West to a club fighting for a playoff berth.
"The last couple of weeks we haven't played really well," Kings goalie Jonathan Quick said. "We got to move forward and string a few wins together. We can get better."
Smyth gave the Kings a 1-0 lead at 10:50 of the first period, ending an 0-for-22 power-play drought that spanned the previous seven games. He scored his 18th goal on a rebound of Jarret Stoll's one-timer after
Boston's Zdeno Chara was sent off for hooking.
"We played solid defense and capitalized on special teams, which we'd been lacking lately," Smyth said.
The Kings outshot Boston 25-20 through the first two periods, but had only one goal to show for it.
That changed at 3:30 of the third, when Loktionov scored from up close off a rebound of Dustin Brown's shot for a 2-0 lead.
Quick made 34 saves to earn his 21st victory of the season and 13th career shutout, putting him fourth on the club's all-time list.
"Quickie played outstanding, gave us a chance, made some spectacular saves," Smyth said. "Sometimes you get pinned back and you get hemmed in your own zone. He rectified that and settled things down for us."
"It we scored, that could have been a momentum changer and probably the whole game is different," Boston goalie Tim Thomas said. "He [Quick] always seems to play a good game against me. I don't know if he gets his rivalry juices up, but having said that they scored both their goals on the doorstep. I can't remember a doorstep chance that we got off a rebound or a puck laying there. The chances were there, but we weren't there."
Better on the road than at home this season, the Bruins came in with a 6-2-0 record in their previous eight games, having scored at least six goals in four of their seven. But they went 0-for-3 on the power play.
"Any chance to put the puck on the net, they did," Chara said. "We were one or two steps behind where we should have been."
Thomas had been equally as good as Quick, with an 8-0-2 mark in his last 10 games. He made 32 saves before being pulled for an extra attacker with 1:57 remaining.
The Bruins got bad news earlier Monday, when center Marc Savard was diagnosed with a moderate concussion as the result of a hit by Colorado's Matt Hunwick on Saturday. The team said he flew back to Boston and there's no timetable for his return.
Savard sustained a concussion in a game against Pittsburgh last March, and the injury kept him out of the rest of the regular season. He returned for the second round of the Eastern Conference playoffs.
Because of post-concussion syndrome, Savard missed the first 23 games of this season and didn't play his first game until Dec. 2 against Tampa Bay. He has two goals and eight assists in 25 games.
- It was the Bruins' first shutout loss since a 3-0 defeat to Anaheim on Dec. 20.
- The Kings earned their first shutout victory since beating San Jose 4-0 on Dec. 27.
- Los Angeles improved to 15-0-0 when leading after the second period.
- It was the first time in eight games the Kings allowed 30 shots or more.
- The crowd of 18,118 was the Kings' 20th sellout.