Blues wasted a 3-0 first-period lead.
Jeff Carter nets the lone goal of the shootout, after the teams went scoreless on a combined 61 shots through overtime.
The Blues coach says, however, that he won't wait long to pull the plug on the experiment if it doesn't work.
Berglund's line has been on the ice for five of Kings' last seven even-strength goals.
Plus: Tonight's lines for each team, and notes on the late start (8:30) for Game 2.
Elliott gets the nod to start Game 1 for the Blues, but will he keep the job?
Jamie Kompon, a former Blues staff member, won a championship with the LA Kings this season.