Lee Stempniak chipped in with a goal and an assist for St. Louis, which improved to 2-4 in preseason play. Doug Weight also added a goal.
Minnesota fell to 4-2 and had its four-game winning streak snapped,
Boyes, a right winger, has a team-high seven points in exhibition play with two goals and five assists. He got the Blues rolling by scoring on the power play 4:27 into the game. He lifted a backhand past goalie Josh Harding. In the second period, Boyes made it 3-1, converting on a scramble in front of the net. Stempniak added a shorthanded goal on a breakaway later in the period to make it 4-1.
Boyes, who had four goals and eight assists in 19 games for the Blues last season, just missed a hat trick. He hit the goal post with an empty net in the final minute.
Weight broke a 1-all tie with a wrist shot from close range at 17:35 of the opening period.
St. Louis goaltender Hannu Toivonen, who will serve as the backup to Manny Legace in the regular season, stopped 24 of 26 shots to record his second victory in three appearances. Harding stopped 15 of 18 shots before giving way to Niklas Backstrom with 8:12 left in the second period.
Copyright by STATS LLC and The Associated Press
Arena: Scottrade Center Location: Saint Louis, Missouri
Brad Boyes (power play) Assist: Martin Rucinsky, Christian Backman
Pavol Demitra Assist: Marian Gaborik
Doug Weight Assist: Brad Boyes, Bryce Salvador
Brad Boyes (power play) Assist: Martin Rucinsky, Martin Kariya
Pierre-Marc Bouchard Assist: James Sheppard, Brian Rolston