With Jamie Benn scoring two of the four goals Dallas got in a span of just more than 12 minutes in the second period, one of those redirecting a flying puck with his stick, the Stars beat St. Louis 5-2 on Thursday night to end the Blues' franchise-record 11-game winning streak.
When Benn scored the game's first goal 3:46 into the second period, the Blues trailed for the first time since Feb. 5 - a span of more than 517 minutes on the ice over 10 games.
Radek Faksa and Alexander Radulov put Dallas up 3-0 with goals in a 65-second span midway through the second period.
The Stars, who are currently in position for a playoff spot in coach Jim Montgomery's first season, snapped a three-game losing streak in which they were shut out twice.
Blues goaltender Jordan Binnington entered the game with a 13-1-1 record and was riding a nine-game winning streak that was a rookie team record. The only other time he allowed four goals was Jan. 21 against the Los Angeles Kings, 4-3 in the last loss for him and the team.
Binnington had 19 saves. The Stars got an empty-net goal from Tyler Seguin in the final minute, the only goal in the game not scored in the second period.
Anton Khudobin stopped 43 shots while starting his seventh consecutive game for the Stars.
Regular starting goaltender Ben Bishop, who missed the previous six games with an upper-body injury, was active and on the bench as the backup after going through an optional practice Wednesday.
Vladimir Tarasenko scored his 27th goal for the Blues on an assist from O'Reilly, who got his 24th goal of the season in the closing seconds of the second period.
The Blues were without C Brayden Schenn, who sustained an upper-body injury in their 3-2 overtime win against Toronto on Tuesday night.
The Blues are at Boston on Saturday.