BUFFALO, N.Y. — When the playoffs started in Buffalo, KeyBank Center was a madhouse. Fans who had waited 15 years for the Sabres to host a playoff game turned the plaza outside the rink into a party. The noise in the building was enough to make your ears ring. And after Game 1 wins in both the first and second rounds, the “Sabres on the warpath!” chants echoed through the atrium as fans exited the building.Thursday night was different. After getting off to a strong start in a wacky first period, the Sabres had a 3-2 lead at the first intermission. They were skating circles around the Canadiens at the start of the second period, but the game flipped when Jakub Dobeš stopped Tage Thompson on a breakaway. Josh Anderson tied the game a few minutes later. Montreal broke the game open from there, taking advantage of Buffalo’s shoddy defensive play to win 6-3 and take a 3-2 lead in the series.By the end of the game, the thousands of Canadiens fans who made the trip to Buffalo had their own party. They poured into the atrium chanting, “Olé Olé Olé Olé Olé Olé!” Then a group of them huddled together and started chanting, “Habs in 6!”This is not what the Sabres had in mind when they gutted out a Game 4 win to bring this series back to Buffalo tied 2-2. Yes, the Sabres have struggled at home this postseason. But this was a chance to flip that script and take the upper hand in this series. Now they’re heading back to Montreal facing the possibility of elimination.“We have it,” Sabres captain Rasmus Dahlin said when asked about finding their game as they face elimination. “We just gotta go on the road because we’re great on the road. We’ll find it.”After a dramatic comeback win in Game 1 against Boston to start the playoffs, Dahlin said he and Thompson always tell each other, “Dogs have to be dogs.” Thompson was one in that game, willing the team to a win with two third-period goals. But this series against the Canadiens has been a different story for the Sabres’ best players.Thompson has two goals and two assists, but he’s also minus-seven. His linemates, Peyton Krebs (zero points, minus-five) and Alex Tuch (zero points, minus-eight) haven’t been much better.The dropoff for Tuch is the most glaring. Against Boston, he was a beast. He had seven points in six games and was plus-eight. In the decisive Game 6, he scored a huge goal to open the game and was all over the ice defensively.This series, Tuch has been nowhere to be found. He said he thought Game 3 was his worst game defensively; this one wasn’t much better. In Game 5, the Canadiens had a 9-2 advantage in high-danger chances when Tuch was on the ice at five-on-five. He’s also been kept off the scoresheet in five straight games.“Offense has been hard to come by for me,” Tuch said. “Think I’ve had a couple opportunities in the last few games. Tonight was nothing till really late, honestly. I’ve got to bear down. I’ve got to be better. I’ve got to – I can’t be – yeah, I can’t play the way I’m playing right now. Just going to be will and determination, but I’ve got to move past it. I’ve got to move on to the next game and I’ve got to be better for the guys in this room.“Decision-making’s got to be cleaned up a little bit, I guess skate a little bit harder, a little bit faster. Just need more of everything.”This entire series has been a struggle for the Krebs-Thompson-Tuch line. During that line’s five-on-five minutes in this series, the Sabres have been outscored 5-0 and outchanced 31-17. The Canadiens have earned 69 percent of expected goals when that line is on the ice for Buffalo.Lindy Ruff tried shuffling that group up in the third period. Ryan McLeod and Konsta Helenius both got a chance to skate with Thompson and Tuch. Then Ruff split up Thompson and Tuch, too. It’s fair to wonder if it’s time to do that for good.“When the game gets where you need a couple goals, you’ve got to put your best players together; they’ve got to play,” Ruff said. “Hard to play four lines when you’re down, because you’ve got to believe in your top guys, and they’ve got to get it done for you.”Those players aren’t getting it done. Thompson failed to cash in on a breakaway attempt in the second period that could have given the Sabres a 4-2 lead. Then he took a careless cross-checking penalty at the end of the second period, and the Canadiens scored to make it 5-3. Dahlin had a cross-checking penalty at the start of the third period, and Montreal scored on that power play, too.The Canadiens got seven points out of their first-liners in this game alone. The Sabres have four points from their first line all series. Montreal’s top line has a 16-4 points advantage on the Sabres’ top line through five games of this series.After a three-goal first period in Game 5, the Sabres’ offense went quiet. That’s when you need Thompson and Tuch, who combined for 73 goals in the regular season, to be dragging the team back into the game. If this becomes the lasting image of this playoff run, Sabres general manager Jarmo Kekäläinen will have a lot to think about in the summer.Tuch, who turned 30 earlier this week, is still unsigned and can become a free agent on July 1. If he hits the market, he will likely be the top free-agent forward available. That fact is hanging over every conversation about his struggles. There will be time to debate his contract whenever the Sabres’ season ends. But what’s not debatable is that right now the Sabres are going to have a hard time climbing out of this 3-2 series hole if he keeps playing the way he has.“I think you get in a series like this, and you’re struggling a little bit, I think he’s lost just a little bit of confidence,” Ruff said. “Trying a little bit too hard to make that extra play. I think number one, the biggest thing is you’ve got to move your feet. Always move your feet, whether it’s through the neutral zone, whether you’re challenging through the blue line. That line just hasn’t been quite connected, and I think it all comes down to skating on pucks in the offensive zone.”That line is far from alone in struggling this series. The Sabres’ puck management and defensive-zone coverage have been far too sloppy against an offensively gifted Canadiens squad. And Buffalo’s goaltending hasn’t been able to bail them out consistently through five games. There’s a lot of individuals who have a lot to correct.The Sabres have had a dream season to this point. But it feels like so much of how this ends will depend on what they get from their best players. Asked if the best players have to be better, Dahlin offered a blunt response in the locker room after the game.“Yup,” he said. “Simple as that.”Dogs have to be dogs, after all.