In the Eastern Conference, it was a double celebration for Martin Brodeur as the
Playoff standout Dustin Brown sparked the Kings' 3-1 triumph with a game-clinching goal late in the first period and an empty netter with 26 seconds remaining in the contest.
"We found a way to bend but not break, and that is something that this team has not relied on," Brown told reporters. "But we found a way."
Netminder Jonathan Quick made 23 saves as he shut-out the Blues for the final two and a half periods.
"He made maybe five or six unbelievable saves off the second shot (in the series), but that's who he is," said St. Louis coach Ken Hitchcock.
"He never quits on the puck. It's a very unique skill."
The Game Four victory came on the heels of a 4-1 series win by the Kings over the Vancouver Canucks, the league's top regular season team, in the opening round of the playoffs.
Los Angeles, in the conference finals for the first time in 19 years, will meet Phoenix or Nashville for the West title.
The Coyotes can clinch their series with the Predators with a win on Monday.
The Kings went 3-1-2 against the Coyotes during the regular season, shutting Phoenix out twice. They won three of four games against the Predators.
Brown broke a 1-1 deadlock with his fifth goal of the postseason after Jordan Nolan had scored for the Kings and Kevin Shattenkirk for the Blues, all in the first.
Brown completed the scoring with his empty netter in the closing seconds.
St. Louis scored just six goals in four games against the efficient Quick.
"We're going to have a long summer of thinking about how we could have been better," said Blues captain David Backes.
In New Jersey, Brodeur, a three-times Stanley Cup champion and the NHL's all-time leader in goaltending wins, fell behind 2-0 in the first period before the Devils rallied for the win to provide him with the perfect birthday gift.
"I'm used to getting these milestones in hockey, not in age, but now I guess I got that one too," Brodeur told reporters after making 20 saves. "We can't take anything for granted, we have to do more of the same."
Dainius Zubrus scored two goals and New Jersey kept the pressure on opposing goaltender Ilya Bryzgalov, who had 39 stops, as they head to Philadelphia for Tuesday's Game Five with a chance to reach the Eastern Conference Finals with a win.
Philadelphia looked poised to tie the series in the first period where Scott Hartnell made a tip-in and Claude Giroux netted his eighth goal of the postseason.
The Devils responded quickly and tied the contest less than five minutes later with Petr Sykora converting a power play and Marek Zidlicky getting his first score of the playoffs.
Zubrus grabbed the go-ahead goal late in the second period and added an empty-netter in the final seconds.