"We're not going to beat [the Los Angeles Kings] if we do not all bring our 'A' game," Vigneault said. "It is that strong of an opponent that we're playing against.
"Our 'B' game won't do it. They're one of the best teams I've seen in a long time. Areas to exploit, they don't jump out at you. We're going to have to be better than we were."
The Rangers went toe-to-toe with the Kings for 40 minutes Wednesday at Staples Center. They played fast and took a 2-0 lead barely 15 minutes into the game. They had the Kings on their heels. But they couldn't keep it that way.
New York's lead had evaporated by 6:36 of the second period when Kings defenseman Drew Doughty scored a highlight-reel goal.
The Kings dominated the third period with a suffocating forecheck that led to a 20-3 edge in shots on goal.
Had it not been for Rangers goalie Henrik Lundqvist, Game 1 would have been decided long before Kings forward Justin Williams turned a Dan Girardi turnover into the overtime winner to give Los Angeles a 3-2 victory and a 1-0 lead in the best-of-7 series.
Game 2 is Saturday (7 p.m. ET; NBC, CBC, RDS).
"In looking back at it, for 40 minutes we went head to head with them," Vigneault said. "When they had a push, we had one guy that had a big push. Our goaltender permitted us to stay in that game. We were one shot away. So I think our group can be better."
His players feel the same way.
Defenseman Marc Staal said Wednesday that it should be a good sign that the Rangers were one shot away from winning a game in which they didn't play at their best for a full 60 minutes.
Center Brad Richards mentioned how now the Rangers have a taste of what it's like to play against the Kings and should be better prepared to handle them in Game 2.
On Thursday forward Carl Hagelin talked about how the Rangers' speed, easily their biggest advantage in the series, gave the Kings fits and resulted in their two goals.
"We think our group has a lot more to give," defenseman Ryan McDonagh said.
Vigneault said nothing about the Kings surprised him -- nor should it. He coached against them for seven seasons in the Western Conference and his Vancouver Canucks were one of the teams L.A. rolled over en route to winning the Stanley Cup in 2012.
"Nothing jumped out at me in the sense that everything that I expected, everything that we had talked to our players about, about what to expect, they did it down to a 'T'," Vigneault said. "They keep doing it. They stay with it. They don't deviate. It's tough to exploit any areas because they're that good."
Now that they're one game in, it's clear to Vigneault and the Rangers that the talk heading into the series wasn't just lip service. L.A. will be New York's most challenging opponent of the Stanley Cup Playoffs.
According to Vigneault's descriptions, the Rangers dispatched the "physical" Philadelphia Flyers in the first round, the "skilled" Pittsburgh Penguins in the second round and the "structured" Montreal Canadiens in the Eastern Conference Final.
The Kings have all of the above.
"This one here is structured, they've got skill, they're physical," Vigneault said. "Makes it a pretty big challenge."
That's why his message Thursday has to resonate with the Rangers.
Nobody beats the Kings in the playoffs without bringing their "A" game in every game. Only one team has been able to do it in the past three years.
"When we played Game 6 against Montreal, each and every player brought his 'A' game," Vigneault said. "It's not an easy thing to do, but against this opponent -- I do believe our expectations are to win -- [we've] got to find a way to do it.
"'B' is not going to cut it against this team."