The Blues were the No. 2 seed in the Western Conference, and the top team standing. Hopes were high for a deep Stanley Cup run given the President's Trophy-winning Vancouver Canucks were out, along with other perennial title threats in Detroit, Pittsburgh and Chicago.
They never got comfortable against a Kings team that beat them at their own game with dogged forechecking, smart physical play, and a defence that never left any gaps in front of an acrobatic goalie who was the star of the show.
"They're the best team that we've played against, so that's all I can judge it on," coach Ken Hitchcock said. "L.A. plays the way you have to play to win the Cup now. I'm sure they've had stumbles along the way to figure it out, but it looks like to me like they've figured it out."
The Blues looked like they had the formula in the first round when they dropped the opener at home in double-overtime to the Sharks and then took four straight.
Getting swept by the Kings minimizes to a certain extent what was a breakthrough season. The Blues topped 100 points for just the fourth time in franchise history, finding high gear after Hitchcock arrived in early November and tying for second-best overall in the NHL with 109 points.
Goalies Jaroslav Halak and Brian Elliott combined for 15 shutouts and the Blues were the NHL's best at home with a franchise-record 30 wins and just six regulation losses. Elliott, who led the NHL in goals-against average, was a star after stepping in for an injured Halak in the first round.
They hadn't won a playoff game in eight years or a series in a decade before dispatching the Sharks. And then it all went flat.
Andy McDonald and Patrik Berglund combined for 15 points against the Sharks, but the top six forwards mustered just seven points against the Kings, with Berglund, T.J. Oshie and Alex Steen going scoreless.
A team built on relentless play unaccountably appeared a step slow much of the series, forced to react instead of dictating terms. Discipline went out the window with numerous ill-timed penalties fueling the Kings' momentum.
In Game 4, a double-minor high sticking call to Scott Nichol postponed the Blues' third-period comeback effort. Matt D'Agostini was whistled for boarding, negating a penalty on the Kings' Dustin Brown for breaking Vladimir Sobotka's stick.
Those types of things happened throughout the series.
"We took penalties at the wrong time," Hitchcock said. "We got emotionally wrapped up during the shift and couldn't shut it down when we needed to shut it down."
Spotty defence too often left Elliott on his own with Brown, Dustin Penner and Anze Kopitar free to dangle the puck near the crease unmolested. Elliott was good, but not great like the Kings' Mike Quick.
Until the second half of Game 4, when defenceman Kevin Shattenkirk led an offensive surge, there wasn't enough traffic in front of Quick.
Injuries took a toll, too.
Star defenceman Alex Pietrangelo missed Game 2 with an injury believed to be a knee, and although he returned for the last two games and led the team in minutes he wasn't the same. Pietrangelo was on the ice for six of the Kings' last seven goals.
Perhaps they were hurt, too. Later this week, it's expected the team will reveal other previously undisclosed injuries that sliced into the productivity.
Worst of all, the home advantage they maintained all year suddenly vanished.
"It's a tough pill to swallow," Steen said. "I don't think we ever got up to our game. Give LA a lot of credit, they played well, but I definitely don't think we played up to par."
So now they're watching and wondering what might have been.
"What we really play for is post-season success," said forward David Backes, the team captain. "This is something that's going to sting but we're going to have to learn from it."
Moving forward, a front office that was patient with a slow-developing youth movement has several decisions to make, perhaps under new ownership if a protracted sale process can be completed. The biggest call: Whether to continue staying the course.
David Perron and Oshie, former first-rounders, and Chris Stewart will be restricted free agents. Among those due for unrestricted free agency are defencemen Jackman, Carlo Colaiacovo and Kent Huskins, and forwards Arnott, Jamie Langenbrunner and Scott Nichol — the veteran trio brought in to speed the development process.