Thomas scored on a one-timer from the left circle at 19:20 for the 6-1 final.
"I thought guys were dialed in pretty good," Berube said. "We really did a lot of good things in the offensive zone tonight. I thought we reloaded tonight. David Perron, I saw him, I don't know how many times, reload tonight, breaking plays up. We transported the puck and got it going the other way quickly. Pretty good effort all around."
The Islanders finished 3-2-0 on their road trip.
"I thought our first period was fine, our power play was good, we had a couple good looks, but they capitalized on their chances," New York coach Barry Trotz said. "When we got down by two, I thought we could kind of dig ourselves out of it in the second and early, we didn't. We turned pucks over, we were really light on the walls and just too many mental errors. It went south, I think, after the third and fourth goals."
NOTES:Islanders forward Casey Cizikas sat out after serving a one-game suspension for boarding Carolina Hurricanes defenseman Brendan Smith on Friday. ... Islanders forwards Mathew Barzal was minus-5 in 15:34 and Zach Parise was minus-4 in 16:40. … New York forward Andy Andreoff was recalled from Bridgeport of the American Hockey League Saturday and played 10:36 in his first game since Dec. 2. ... Thomas has 17 points (six goals, 11 assists) in an NHL career-high nine-game point streak, with seven multipoint games. ... Barbashev had an assist to give him eight points (four goals, four assists) in a six-game point streak. ... Faulk has 11 points (five goals, six assists) the past seven games. Only three defensemen in Blues history have a longer goal streak (Alex Pietrangelo, four, 2013-14; Brian Benning, four, 1986-87; Larry Sacharuk, four, 1974-75). ... St. Louis forward Pavel Buchnevich had an assist to give him nine points (four goals, five assists) in a six-game point streak and 12 points (six goals, six assists) his past nine games. ... Blues forward Brandon Saad had an assist in his 700th NHL game. ... Parayko's assist was his 200th NHL point. ... St. Louis has scored four or more goals in each of its past eight games. ... Kyrou returned after missing Friday due to illness; he had two assists in 13:29 and returned in the second period after being sent to the locker room following a hit by Islanders defenseman Zdeno Chara.