Rookie Patrik Berglund scored twice in the third period to end a 10-game goal drought and Mason made 22 saves for his fifth shutout of the season in a 2-0 victory over the Los Angeles Kings on Tuesday.
"We could have played a lot better in the first 40 minutes, but we finally scored," Berglund said. "And Mason played unbelievable."
David Perron assisted on both goals for the Blues, four games above .500 for the first time while attempting to end the franchise's three-year playoff drought. St. Louis has 77 points, one point behind Nashville and Anaheim for the final spot in the Western Conference, with nine games to go.
"It's the desperation, it's the urgency, it's the no quit in this team," Mason said. "In the third period, we just turned it on."
The fading Kings are in a 1-5-1 slump and are 2-9-1 in their past dozen games on the road. They walloped the Blues three straight times earlier in the season, but this was the first meeting since Dec. 11.
Coach Andy Murray said that was a much different team then, adjusting to top forward Andy McDonald's broken ankle and the loss of other frontliners.
"We stuck with it, we maintained our composure," Murray said. "It was a kind of game where earlier in the year, we don't possibly handle as well."
Berglund, limited to two assists the previous 10 games, got the first two-goal game of his career. The biggest came on a tap-in at 7:56 of the third when Perron's drive from the left side missed everything and rebounded right to his stick. He twice swatted a puck loose in the crease after T.J. Oshie's shot trickled through Jonathan Quick, converting on the second attempt for his 19th of the season at 13:13.
Quick said the shot also deflected off a player in front of the net.
"I believe it hit a chest, arm, something up there," Quick said. "I just lost the puck in the jersey and it must have fallen behind me."
Despite scoring once in the previous 22 games, the 20-year-old Berglund leads the Blues with a plus-minus of plus-17. His linemates are Perron (20) and Oshie (22), all first-rounders.
"Yes, it was a long time," Berglund said. "So it was really nice."
Mason, who made his 24th straight start, was at his best in the first period when the Kings had an 11-4 shots advantage. Seven of Los Angeles' shots in that period came on consecutive power plays.
"A lot of blocked shots," coach Terry Murray said. "That's one thing they do well, they block well and they get in the lanes. We were doing the same, we did a real good job until the end."
- Kings F Alexander Frolov, second on the team with 55 points, will be out seven to 10 days after a collision with the Blackhawks' Brent Seabrook on Sunday in Chicago.
- Blues F Keith Tkachuk, who missed one game after getting struck in the left wrist by a slap shot, returned to the lineup.
- Kings D Peter Harrold played in his 100th career game, all with Los Angeles.