''To be honest, I was, like, `Here we go again,''' he said.
Turns out, he was worrying over nothing. Instead of falling extending their five-game losing streak, the Senators took off and took care of Columbus.
''Right after that (Columbus goal) we took the game over again,'' Lehner said after making 32 saves and earning his first win of the season. ''We kept on grinding, and they weren't in our zone for a while.''
Lehner more than filled in for Craig Anderson, who was sidelined with a sore neck after a collision with Dallas rookie Valeri Nichushkin on Sunday. He made several big stops that kept the Senators in the lead and helped give them confidence.
''It was nice to get this one and, obviously, Robbie played unbelievable and made the stops we needed him to make,'' Karlsson said. ''He's done a good job covering for Andy so far.''
Jason Spezza added two assists as the Senators built some steam heading into the start a five-game homestand Thursday night against Montreal.
''It was another good step for us,'' coach Paul MacLean said. ''I thought we played a real solid 60 minutes. There were some times when the opposition had some good play, but we handled the momentum swings better. Our penalty-killers were outstanding.''
R.J. Umberger scored a power-play goal from his knees for Columbus, which lost its fourth in a row. The Blue Jackets failed on three other chances with a man advantage, including one in the final minutes before Karlsson closed the scoring with an empty-net goal.
The Senators are 4-3-2 on the road but just 1-3-2 at home.
Lehner became the second straight backup to stymie the Blue Jackets. Pittsburgh's Jeff Zatkoff beat them 3-0 on Saturday.
Down 2-0, the Blue Jackets cut the deficit in half 3:02 into the third period.
Umberger ended up on his knees in the slot, stealing the puck off the stick of defenseman Chris Phillips and then whipping a shot past Lehner, who came in with an 0-2-2 record and a 2.73 goals-against average.
The goal ended a drought of 103 minutes, 48 seconds for the Blue Jackets.
Asked if his team was lacking confidence with the puck or was just frustrated, Columbus coach Todd Richards said both things are factors.
''It's in our game right now,'' he said. ''It's not just with the puck. (Lack of) confidence, and frustration. That comes with losing games.
''What we have to do is find solutions to win hockey games. It was a 2-1 game in the third. There was an opportunity and we let it slip away.''
After the Senators killed off a penalty, Neil -- who had two fights in the third period -- pushed the lead to 3-1 with just 6:05 left.
''It was kind of a broken play,'' Neil said. ''Spez picked it off in the neutral zone, I came out on a line change, and it ended up being a 3-on-2. I called for the drop and used the defenseman as a screen.''
The Senators were outshot 13-9 in the first period, yet built a two-goal lead.
The first came at 14:51 when Karlsson collected a turnover in the neutral zone, coasted to the right dot, and lifted a wrist shot that beat goalie Curtis McElhinney high on the glove side for his fifth of the season.
Karlsson extended his point streak to five games (4 goals, 5 assists).
With 3.9 seconds left in the opening period, Kyle Turris shot wide left on a rush. Bobby Ryan pulled the puck off the back wall and backhanded a blind centering pass to MacArthur, who was alone at the doorstep for a one-timer.
''I'd say it's frustration,'' said McElhinney, who started his second game in a row to give 2012 Vezina Trophy winner Sergei Bobrovsky time to work on tweaking his game after a slow start. ''We're getting opportunities (to score). Two of the last three games we've put tons of pucks on net, but Robin was terrific tonight.''
- Columbus LW Nick Foligno didn't play due to a personal matter.
- The Blue Jackets recalled C Sean Collins from AHL Springfield.
- Turris also extended his point streak to five games (1 goals, 6 assists) with an assist on MacArthur's goal.
- Columbus signed 2012 fourth-round draft pick Josh Anderson to a three-year, entry-level contract.
- Blue Jackets RW Jared Boll played in his 400th NHL game.