St. Louis, which has won five of six, moved into fourth place in the Western Conference. The Blues have 58 points, one ahead of Los Angeles and San Jose. They can clinch the No. 4 seed and home ice in the opening round of the playoffs with a victory over Chicago on Saturday.
Los Angeles and San Jose will meet Saturday in the final regular-season game for both teams.
Calgary, which will miss the playoffs for the fourth straight year, has won five of eight but will end the season Friday at Chicago.
Elliott made 18 saves in improving to 10-2 in April. He has three shutouts in the month and has allowed only 15 goals.