Los Angeles' Justin Williams scored 4:36 into overtime after a turnover by Dan Girardi, giving the Kings a 3-2 home win over the New York Rangers in the opening game of the NHL's Stanley Cup finals.
Kyle Clifford had a goal and an assist for Los Angeles, and Drew Doughty made up for an early mistake by scoring the tying goal in the second period.
Jonathan Quick made 25 saves as the Kings moved one victory closer to their second Stanley Cup title in three years.
"It certainly helps that we've done it time and time again,'' said Williams, the repeat postseason hero dubbed Mr Game 7 for his knack for series-deciding goals.
"It's a great result of the hockey game for us, definitely, but we have a lot of things to clean up. Certainly not our best game by any standards, especially ours, but we were able to get it done. That's the most important thing.''
Game 2 is Saturday in Los Angeles.
The series is big news in the nation's two biggest cities. The last time a New York and Los Angeles team clashed in a major league decider was when the Yankees took on the Dodgers in baseball's World Series in 1981.