Coming off a shootout win over Detroit on Tuesday night, the Blues won consecutive games at home for the first time since Jan. 14-16.
St. Louis improved its home record to 11-16-5, still the worst in the NHL, while Toronto lost for the sixth straight time on the road to drop to 8-18-6 away from home, the league's worst road record. The Maple Leafs are 2-13-2 on the road since Dec. 5 and were playing in their last game before the Olympic break.
"Maybe our minds weren't where they should be," Toronto coach Ron Wilson said. "This is our last game. I thought we made some bad mistakes. We made it pretty easy for them. They just played better than us. We didn't play very well."
McDonald opened the scoring with 5:38 remaining in the first period. On a 3-on-1 break, Erik Johnson's initial shot was stopped by Jean-Sebastien Giguere, but Patrik Berglund grabbed the loose rebound and fed McDonald alone by the right post. McDonald jammed the puck past Giguere for his 19th goal of the season.
"We've got to work hard every night," Rickard Wallin said. "They won more battles than we did especially in the second period. That's where the game kind of slipped away from us."
Mason faced his biggest challenges in the third period when Toronto peppered him with 15 shots, but he stopped them all for his 20th career shutout.
St. Louis made it 2-0 at 9:07 of the second period. With David Perron in the penalty box for interference, David Backes intercepted a Toronto pass in the Maple Leafs' zone and tried to score on a wraparound. Giguere made the initial save, but the rebound came straight out to Oshie for his 12th of the season.
The Blues got their second short-handed goal of the period when Steen scored an unassisted goal, his 15th of the season. The former Toronto player circled behind the net and backhanded a shot through Giguere's pads.
"Obviously [Oshie] capitalized on one," Backes said. "And Alex Steen did a great job on winning two or three behind the net and comes around and stuffs one in their net."
St. Louis hadn't scored two short-handed goals in a game since Jan. 16, 2007, when it beat Anaheim 6-2.
Blues C Keith Tkachuk was scratched because of an upper-body injury. ... Toronto RW Phil Kessel's points streak ended at five games. Kessel had six goals and four assists in his previous five games. ... Toronto hadn't played in St. Louis since beating the Blues 2-1 on Feb. 6, 2007. ... The announced crowd of 19,150 was the Blues' 25th sellout of the season.
Copyright by STATS LLC and The Associated Press
Arena: Scottrade Center Location: Saint Louis, Missouri
Referees: Ghislain Hebert Linesmen: Jonny Murray
Attendance: 19,150 (100.0% full)
Team Stat Comparison
Power Play Goals
Power Play Opportunities
Shots on Goal
Andy McDonald (19)
Assists: Patrik Berglund, Erik Johnson
T.J. Oshie (12)
(Shorthanded) Assist: David Backes
Alexander Steen (15)
B.J. Crombeen (5)
Assists: Jay McClement, Carlo Colaiacovo