"You know we only played 40 [minutes] tonight when we need to play 60," Green said. "If it wasn't for Jose, it would have been a lot different game."
Theodore had 34 saves and improved to 18-0-3 with a goals-against average under 2.70 since Jan. 13, extending his own Capitals record for decisions without a regulation loss.
Washington set a franchise record with its 51st win of the season. The victory also drew the Capitals nearer to clinching the Presidents' Trophy for the best record in the NHL. They need only another win or a San Jose loss to grab that trophy for the first time -- and home ice throughout the playoffs.
The Caps added to their franchise record for points in a season (114) and set a new mark for road wins (23).
"Well, it's nice to set records," Capitals coach Bruce Boudreau said. "It gives us a goal to shoot for for next year. And it's nice to get the 51st win. We were stuck on 49 there for a while. But its more significant the fact that Theo had a good game and for the most part we played fairly good defensively."
The Caps led 3-1 for almost 40 minutes until Vermette converted his second goal of the night off Nash's feed from the back wall to Vermette, alone in the slot.
Theodore made several strong saves in the waning moments, preserving the lead when R.J. Umberger's shot slid just wide of the far post with 3 minutes left.
The vaunted Washington offense, the most prolific in the league at 3.80 goals per game, flexed its muscles three times in the opening period.
After Theodore turned aside a couple of quality Columbus chances, Semin took a short bump pass from Brooks Laich, settled the puck and rocketed a shot past goalie Mathieu Garon for his 38th of the year.
Garon was knocked to the ice by former teammate Jason Chimera -- traded by Columbus to the Capitals in a December deal -- and the Blue Jackets' Anton Stralman picked up a penalty on the play. Garon was on the ice for several minutes before play resumed.
Just seconds after that power play ended, the Capitals struck again when Eric Fehr dug the puck off the back wall with a blind behind-the-back pass to Mike Knuble, who saucered a setup pass for Fleischmann.
That was it for Garon, who had two saves on four shots. He was replaced by Steve Mason, who was held out of the lineup while recovering from a slight shoulder injury sustained in a 3-2 loss at Detroit on Thursday night. Mason finished with 22 saves on 23 chances.
The Capitals made it 3-0 on a 5-on-3 advantage, Green scoring unassisted on a hard slap shot from the top of the right circle. The goal gave him a career-best 74 points.
"I just kind of got lucky with keeping it in," he said. "They took Ovi [Alex Ovechkin] away and Brooks [Laich] made a great play on that. I just had to put it in."
The Blue Jackets got on the board at the end of that two-man disadvantage. Nash chipped the puck away from defenseman Joe Corvo between the penalty boxes, then swooped up the right wing. He waited for a sliding Corvo to clear out of the way before feeding Vermette for a jam shot for his 26th goal while short-handed.
The Capitals, unlike the Blue Jackets, were able to kill a lengthy 5-on-3. Columbus had almost 1½ minutes with two extra men in the second period, but never really threatened.
"The 5-on-3 on both sides, I thought was a general turning point in the game," Vermette said. "We have to look at what we did out there and try to optimize our chances and try to get some better scoring chances."
The Blue Jackets are trying to just play out the season despite missing several of their top players who are out with injuries.
"We battled through, even though our lineup's not at its best right now," interim Blue Jackets coach Claude Noel said.
With just one goal in his last six games, Ovechkin remains stuck on 133 career goals at home and 133 on the road. He didn't have a shot in the first two periods and finished with two. ... Umberger's six-game points streak came to an end. ... Columbus RW Derek Dorsett played in his 100th NHL game.
Copyright by STATS LLC and The Associated Press
Arena: Nationwide Arena Location: Columbus, Ohio
Referees: Dean Morton, Stephane Auger Linesmen: Pierre Champoux, Tim Nowak
Attendance: 16,957 (93.5% full)
Team Stat Comparison
Power Play Goals
Power Play Opportunities
Shots on Goal
Alexander Semin (38)
Assists: Brooks Laich, Tyler Sloan
Tomas Fleischmann (22)
Assists: Mike Knuble, Eric Fehr
Mike Green (19)
(Power Play) Unassisted
Antoine Vermette (26)
(Shorthanded) Assist: Rick Nash
No scoring this period
Antoine Vermette (27)
Assists: Rick Nash, Marc Methot