Max Pacioretty scored his seventh NHL hat trick, and Mark Stone had three assists for Vegas (5-1-1). Robin Lehner made 21 saves in his second consecutive loss.
"We have such good structure on this team that it doesn't change much other than everyone being on the same page and the different voice behind the bench," Pacioretty said. "We all take pride in our systems. We work on them on a daily basis, whether it's during practice or on video."
Alex Pietrangelo was plus-1 with an assist in 28:57 in his first game against the Blues since the defenseman signed a seven-year, $61.6 million contract with the Golden Knights after playing his first 12 NHL seasons in St. Louis.
"Honestly, it felt like a normal game," Pietrangelo said. "I think once you get out there and you start playing, that kind of all gets pushed to the side. First couple shifts, obviously it's a little bit different, but I think once we settled in, I felt fine."