"It's always nice to beat the top team in the conference, but we're not looking at this like anything crazy," Poti said. "It's two points in the bank and let's move forward."
Aaron Voros netted the lone goal for the Rangers, who have dropped three of four. Henrik Lundqvist stopped 25 shots in the loss.
After a scoreless second period, Voros brought the Rangers within 2-1 at 6:27 of the third with a power-play tally.
Johnson came up big nearly three minutes later, as Chris Drury was awarded a penalty shot while the Rangers were shorthanded. The New York captain went to the far post for his shot but Johnson closed off the area to prevent a goal.
"I just came out and challenged as much as I could," said Johnson. "He was close enough on the backhand that I got my stick on it."
Things got dicey for the home team when Semin was sent off with 2:15 to play in regulation for tripping.
Johnson was in control, though, making a glove save from a right-point shot from Scott Gomez and two more from in close on scrambles. Those were three of his 13 third-period saves.
The young Russian exited the box just in time to slam an empty netter from inside his own right circle to clinch the contest with six seconds remaining.
Laich's third goal of the season, a power-play marker, got the Caps on the board 9:14 into the contest. Poti potted his first of the year with 2:54 to play in the first and the Caps went up 2-0.
"I think we bounced back pretty good. Unfortunately, our best period was the third period," noted Lundqvist. "We made it a little tougher for their forecheck but still came up short."