Rittich, who sat the previous six games behind Cam Talbot, notched his second shutout of the season. He also made 26 saves in a 4-0 win over the Edmonton Oilers on February 10.
Adrian Kempe, Philip Danault and Trevor Moore scored for the Kings, who took over sole possession of third place in the Pacific Division, two points ahead of the Vegas Golden Knights.
Ilya Sorokin recorded 22 saves for the Islanders, whose six-game winning streak was snapped.
Rangers 3, Devils 1
Jonathan Quick made 19 saves and New York scored twice in the final eight minutes of the second period en route to a victory over visiting New Jersey.
The Rangers won their second straight after following up their 10-game winning streak with three losses in four games and pushed their lead in the Metropolitan Division to four points ahead of the Carolina Hurricanes, whom they visit Tuesday.
Quick picked up his 389th career win to tie Hall of Famer Dominik Hasek for 15th on the all-time list. He also moved within two of tying Ryan Miller for the most wins by an American-born goalie. The Rangers' Mika Zibanejad reached 20 goals for the seventh straight season.
Blues 5, Bruins 1
Kasperi Kapanen matched his career high with three points, collecting a goal and two assists while leading St. Louis past hosts Boston.
St. Louis, which is 26-3-1 when scoring first, snapped a three-game skid and broke the three-goal mark for the first time in nine games. St. Louis goalie Joel Hofer made 36 saves.
Boston had a four-game point streak (3-0-1) ended despite David Pastrnak's 41st goal of the season and 17 saves by Jeremy Swayman.
Jets 3, Capitals 0
Connor Hellebuyck made 23 saves for his fourth shutout of the season as Winnipeg beat visiting Washington in the opener of a three-game homestand.
Neal Pionk, Alex Iafallo and Kyle Connor scored for the Jets, who had lost two of three. Hellebuyck logged his 36th career shutout.
Charlie Lindgren made 26 saves for the Capitals, who had scored 10 total goals while winning their previous two games. Washington were opening a five-games-in-eight-days road trip. Washington forward T.J. Oshie played 16:06 and had a minus-2 rating in his return after missing seven games with an upper-body injury.
