After the Stars killed off a full 5-on-3 power play, Robertson scored at 18:31 of the second to cut it to 2-1. He was sprung by Roope Hintz after Justin Faulk turned the puck over trying to backhand it into the offensive zone near the blue line.
"We just got a very big kill," Robertson said. "I got on the ice and I was kind of fresh. I was trying to get open and they found me and I was able to score.
"Our PK was excellent. [Wedgewood] made some big saves. It’s unfortunate we weren’t able to tie it up."
The Blues had eight shots on the power play before Robertson scored.
"We do a good job," Wedgewood said. "I felt like I had some good reads, and I knew what they wanted to do. When it’s 5-on-3, it’s obviously give it your all. These guys know what they’re going to get from it is a little bit of old school, a little bit of a road hockey goalie. We scrambled there in the crease. You’re on your stomach. That brought me back to the road hockey days of playing with my brothers."
Dallas outshot St. Louis 15-5 in the third, but Hofer was able to prevent it from tying the game.
"He was unbelievable," Scandella said of Hofer. "Huge stops. Very confident out there, never looked like he was panicking. Hopefully we can get more of that."
NOTES: The Blues are 15-1-0 when scoring first and 15-2-1 when holding the opposition to three or fewer goals. ... The Stars' only two losses their past six games have come against St. Louis. Dallas lost 4-3 in overtime here on Dec. 16. ... Hintz has four points (one goal, three assists) in a four-game point streak.