OTTAWA (AP) -The Ottawa Senators want to finish the regular season in playoff form.
Antoine Vermette and Christoph Schubert also scored for the Senators, fifth in the Eastern Conference with 89 points, two more than the New York Rangers.
Ottawa remained three points behind Montreal, the leader in the Northeast Division and the East. The Canadiens won 4-2 in Boston on Thursday and have played one more game than the Senators.
"It's going to be an exciting couple of weeks," center Mike Fisher said. "There are a lot of huge games and teams fighting for spots, and it's going to be like the playoffs because we need wins, too, and we're trying to get our full game back."
Gerber made his ninth straight start for Ottawa, which has eight games left - home and away against each of its four division opponents.
"It's kind of good, the fact that we play our division the rest of the way," Spezza said. "It makes for tough games, but it gets you ready for the playoffs."
Jamal Mayers and Jeff Woywitka scored 2:44 apart midway through the first period to give St. Louis a short-lived 2-1 lead.
Schubert scored his seventh goal later in the first to tie it at 2 and Spezza restored Ottawa's lead 7:39 into the second when he drove the net and deflected Dany Heatley's pass out of the air to redirect the puck beyond Hannu Toivonen.
"They've got a couple of players that are among the best players in this league," Toivonen said. "They showed some skill out there. That was a pretty goal, so hats off to them."
Blues defenseman Barret Jackman left St. Louis short-handed for 4 minutes with 8:20 remaining in the game when he had an unsportsmanlike penalty added for arguing after he was called for high-sticking Fisher.
"We didn't capitalize but we still didn't allow them any chances," Fisher said. "For the most part we played a pretty solid game. It was a good win for us to find a way. That's what you've got to do at this time of year, and just build off of it."
Toivonen made 21 saves for the Blues, who avoided setting a franchise record Tuesday when they ended a 10-game road losing streak with a 4-3 shootout win in Montreal.
"I thought he made some good saves, and we'll continue to evaluate him," Blues coach Andy Murray said.
St. Louis is 1-6-1 on its season-high, nine-game road trip, that ends Sunday in Chicago.
"There wasn't a lot separating the teams," Murray said. "We've had an inability to score goals at key times. We had lots of chances to get a lead. When it was 2-1 we had a chance to go up even more and didn't capitalize on our chances."
Vermette gave Ottawa an early lead when he took Chris Kelly's centering pass and beat Toivonen for his 18th goal at 2:06.
Mayers tied it at 9:29 as he was left alone in front of Gerber to redirect in Jackman's shot from the left point.
Woywitka put the Blues ahead with his second goal at 12:13.
Schubert drew the Senators even at 2 when he beat Toivonen with a shot from the slot on Dean McAmmond's centering pass from behind the net.
Notes: The Blues hadn't played in Ottawa since a 3-1 loss on Feb. 10, 2004. ... Spezza has a five-game point streak, recording four goals and three assists. ... RW Brian McGrattan was the only healthy scratch for Ottawa, which returned LW Nick Foligno to Binghamton (AHL) earlier Thursday.