Dobson tied it 1-1 at 17:52 with a one-timer from the right hash marks.
Ivan Barbashev gave the Blues a 2-1 lead at 3:51 of the second period on another 2-on-1, and Ryan O'Reilly pushed it to 3-1 at 14:58 when he swatted in his own rebound while falling down in front.
"It's a good bounce," O'Reilly said. "Just whacking it and got a good bounce there, so I'll take it.
"It's really nice to win. It's a feeling we haven't had in a while. Again, made it a little too exciting at the end there, but the big thing is we won a game. There's a lot of good things we did tonight … there's something to build off there."
NOTES: Islanders defenseman Adam Pelech left midway through the third period following a hit by Blues defenseman Robert Bortuzzo. Lambert did not have an update postgame. … Greiss played with the Islanders from 2015-20. … Blues defenseman Nick Leddy, who played with the Islanders from 2014-2021, was honored with a video tribute during a stoppage in the first period. "I think they did a great job with it," Leddy said. "Obviously, I really appreciate it." … Blues forward Pavel Buchnevich (lower body) and defenseman Torey Krug (upper body) did not play after each was injured in a 6-4 loss to the New York Rangers on Monday. … Blues forward William Bitten had the primary assist on Barbashev's goal for his first NHL point.