Steen, who was the third NHL player in 20 years with 11 goals in his first 10 games of a season, extended his career-best goal streak to six games, the longest in the League. Steen was tied with San Jose Sharks forward Patrick Marleau, who had a five-game streak from Oct. 10-19.
"I think we've talked enough about that," Steen said of his scoring. "I thought tonight we played OK. I think [Elliott] is the reason we ended up winning the hockey game. He made some timely saves, some really big saves, and pretty much stood on his head at times tonight. He really pulled out a W for us."
Steen, who scored eight goals in 40 games last season and whose career-high is 24 goals, has scored in every game but one this season. Named earlier Friday as the NHL's First Star of the Month for October, he made it 4-0 at 10:42 of the second period when he converted a rebound after David Backes skated in from the left side and put a backhand on net.
"The guy is unreal," Elliott said of Steen. "I thought he's been one of the best players in the NHL for a while. He does everything right on the ice. When stuff like this goes well for a good guy like he is, one of the most-liked guys in the locker room, everybody is pulling for him. It's awesome to see it."
Elliott, making his second start of the season, recorded his first shutout since April 11, 2013, a 2-0 victory against the Minnesota Wild. He didn't have to make many tough saves against the Panthers, but did stop Tomas Fleischmann alone in front of the net with 4:57 left in the third period.
"It was good to get in there," Elliott said. "Guys got me a lead pretty early. You kind of just settle in and start seeing the puck. The D blocked a lot of shots, the forwards blocked shots, and when they didn't, they were blocking out the guys so I could see it. It was a good outing."
The victory completed a dominating two-game sweep in the season series for the Blues, who shut out the Panthers 7-0 at Scottrade Center on Oct. 5.
"We're bearing [down] on opportunities, it seems, on their goalies," Pietrangelo said. "It wasn't our best game tonight, but we found a way to win. Obviously the last game was a little bit different, being 7-0, but [Elliott] played fantastic tonight, well-deserving of the shutout."
This was the third time this season the Panthers were shut out. Florida was blanked 3-0 at home by the Los Angeles Kings on Oct. 13.
The Panthers begin a stretch of nine out of 11 games away from home Saturday against the Washington Capitals, who defeated the Philadelphia Flyers 7-0 Friday. Florida (3-8-2) has lost seven of eight, and wrapped up their season-long six-game homestand 1-3-2.
"It's disappointing for all of us," Panthers coach Kevin Dineen said. "Everybody feels bad about it. Understanding that you are playing in the best league in the world and you are absolutely privileged to be in this League, there's no entitlement. And if you don't go out there and play as hard as you can, you will stumble along as we did tonight. The effort wasn't good enough to compete against one of the top teams in the NHL."
After saying the Panthers "probably had three competitive players" against the Blues, singling out forwards Shawn Matthias and Jesse Winchester, and defenseman Mike Weaver, Dineen hinted changes to his lineup might be coming.
"We are going to examine all our options right now," he said. "We've got options we can take advantage of. We're at the point now that it's not about skill for this group, it's about us trying to find the guys that are going to give us the best effort. That's what we'll do in [Washington], put guys out on the ice that will just go out and work as hard as they can for that Panthers logo on the front of the jersey."
The Blues (8-1-2) started a three-game road trip. St. Louis played the fewest games in the NHL in October but will play 15 times this month. That should mean more work for Elliott, the backup to Jaroslav Halak.
"Elliott was great," Blues coach Ken Hitchcock said. "He was really good early and he was really good late. I'm really happy for him. We need him to be sharp. We need to get back to the formula that we had two years ago and that's what we're aiming to do. So he's going to get another start here pretty quick and hopefully we can keep going."
St. Louis came in with the best power-play percentage in the League at 28.2 and scored with the man-advantage when Pietrangelo made it 3-0 at 7:06 of the second. He put in a loose puck at the side of the net after Backes' one-timer from the left circle went off the leg of one Panthers defenseman (Weaver) and off the stick of another (Erik Gudbranson).
Roy got a fortuitous bounce when he opened the scoring 15:41 into the game. His backhand from close range hit the right post, bounced back toward the middle, and trickled in after hitting Markstrom in the back of the leg.
Stewart increased the lead to 2-0 at 5:21 of the second period with his first goal of the season when his one-timer from below the left circle found its way through Markstrom's pads.
"He's been guilty of overpassing or trying to make the next play," Hitchcock said of Stewart. "He's lost a little bit of confidence. Hopefully that gives him [some]. After that, he got three or four quality scoring chances, so that's a real good sign for us."
St. Louis center Maxim Lapierre returned after serving a five-game suspension for a hit on Sharks defenseman Dan Boyle in a game Oct. 15.