LOS ANGELES (AP) -- The Los Angeles Kings' improbable playoff run makes more sense with each victory. This talented team has traded in its season-long inconsistency for metronomic precision, and the Western Conference's top two teams haven't been able to interrupt it.
Although the Kings are eighth seeds, even the powerful Blues agree they've been an unstoppable force so far -- and St. Louis has just one more chance to slow it down.
Drew Doughty had a goal and two assists, Jonathan Quick made 18 saves and the Kings moved to the brink of an unlikely second-round sweep with a 4-2 victory over the Blues in Game 3 on Thursday night.
Mike Richards scored Los Angeles' first power play goal in six games before setting up Doughty's clinching goal with 11:48 to play for the Kings, who methodically improved to 7-1 in the postseason with their third straight dominant win over second-seeded St. Louis.
"They're full marks," St. Louis coach Ken Hitchcock said. "They're on top of their game, and they have been for a while now."
And they just keep doing it with remarkable efficiency and style. Los Angeles has four chances to clinch its first trip to the conference finals since 1993.
Game 4 is Sunday.
"Things are going well because guys are working hard," said Justin Williams, who scored the Kings' first goal. "Guys are paying the price and doing every little thing. We're certainly not looking ahead just yet, but we've fought hard to get this position, and now we're one game away from getting to the conference championship."
Rookie Dwight King also scored, while Anze Kopitar had two assists in just the Kings' second home playoff victory in their last eight games at Staples Center. The Kings barely scraped into the playoffs last month, but after eliminating Presidents' Trophy-winning Vancouver in the first round, they followed up two series-opening victories in St. Louis with another fundamentally sound effort in front of Quick.
"When you have success, you gain confidence, and we've been playing the same system and the same style for a while now," Richards said. "We're maybe a little surprised it's going like this, but we knew going into every game we have a chance to win."
Chris Stewart scored two goals and Brian Elliott stopped 18 shots in a shaky performance for the Blues, who must accomplish the fourth comeback from an 0-3 deficit in NHL playoff history to advance.
Elliott's season-long tandem with Jaroslav Halak was wiped out by Halak's ankle injury in the first round, and Elliott hasn't looked comfortable alone in the spotlight. King, Richards and Doughty all scored on what appeared to be stoppable shots against Elliott, who dropped to 3-3 since replacing Halak while allowing nine goals on 43 shots in the last two games.
"With our team, there is no reason we should be down three games right now," right wing Matt D'Agostini said. "But we are the type of team that is very capable of coming back in this series. There is a lot of promise still in this room and we have a lot of belief in our guys and what we can do, so don't count us out just yet."
The Blues put Pietrangelo back in their starting lineup after the star defenseman missed Game 2 with an injury resulting from King sending him into the boards hard in the series opener. Pietrangelo had an assist, but the Kings minimized his effectiveness after captain Dustin Brown crunched him along the boards in the opening minutes.
"I think our bigger problem is stupid penalties," Hitchcock said. "That takes us out of the 5-on-5, and that wastes energy because we use our best players to kill penalties. I would say they were more physical than we were."
Richards' second-period goal snapped an 0-for-30 drought for the Kings' power play, and Los Angeles' penalty killers kept St. Louis scoreless in 14 power plays in the series. Doughty, the Kings' streaky $56 million defenseman, even added the first multipoint game of his playoff career.
The Kings are 5-0 away from Staples Center in the postseason, and they attempted to retain that road momentum by creating a road trip at home. The Kings staying in a hotel across the street Wednesday night and held their game-day skate at Staples Center, a rarity during the regular season. Los Angeles coach Darryl Sutter took advantage of a three-day break between home playoff games for their two NBA co-tenants at Staples Center, the Lakers and Clippers.
After several near-misses in front of Elliott early, Williams scored his 13th career playoff goal when his wide shot across the crease hit Elliott's sprawling back leg and slid into the corner of the net.
Stewart evened it in the second, backhanding a shot past Quick -- but just 40 seconds later, Matt Greene banked a long pass off the boards to King, and the 22-year-old beat Elliott to the far post for his first career playoff goal.
Richards put the Kings up 3-1 with a sharp-angled shot that somehow trickled through Elliott for his third goal of the postseason. The Blues went roughly 10 minutes without a shot spanning the second and third periods, but Stewart trimmed the Kings' lead back to one goal by diving to tap home a rare loose rebound off Quick with 15:25 to play for his second career multigoal playoff game.
Richards then advanced the puck and made a drop pass to Doughty, whose fierce shot trickled underneath Elliott and rolled in.
NOTES: Richards had a Gordie Howe hat trick after fighting Jamie Langenbrunner in the first period. ... Blues C Jason Arnott was scratched for the first time in the postseason. He missed practice Wednesday with a lower-body injury. ... St. Louis has rallied from an 0-2 playoff series deficit just once in 15 previous tries in franchise history. The Blues came back to beat the Minnesota North Stars in 1972 -- four years after the Blues and Kings joined the NHL together in 1967-68.