Cobus Reinach insists Saints simply have to slay the Dragons at Rodney Parade on Friday night.
The black, green and gold go in search of their first Challenge Cup win of the season after last Saturday's 41-20 home defeat in the curtain-raiser against Clermont Auvergne.
The Dragons started their European campaign with a comfortable success in Romania, as Timisoara Saracens were beaten 54-17.
And Reinach knows Saints can't afford to slip further behind the two early pacesetters in Pool 1 on Friday night.
"It's a must-win for us," said the South African scrum-half.
"We played them in pre-season (when Saints won 42-10 at Rodney Parade) and they were tough. Now they even have more players back.
"They're going to come at us, be very physical and once they get space, they've got players like Jordan Williams who can open you up.
"We need to dominate everything, be more physical than them and when we send the ball out wide, we need to beat them one on one.
"We need to put our game on them."
Saints have lost five of their seven matches in all competitions so far this season.
But Reinach said: "The results we've had have not shown what we did.
"In the Gloucester game, the Bath game, we lost rather than them beating us.
"If we'd got those wins, we could have been in a much different place now.
"We're on a knife edge, we just need to glue bits of our game together to get the whole game working.
"It's little micro-skills we need to work on.
"We need to spend more time on it and be confident in what we're doing to put it on teams."
Like the team as a whole, Reinach has endured a mixed start to the season.
But he feels his own game is not going too badly.
"We as a team played well in a few games and it's easy for a nine to play," he said.
"Personally, I think my game is going well.
"There are one or two games we've struggled in with wet weather but we'll get on top of that."
One of Reinach's main attributes is his acceleration and it is an area he works hard on.
"In pre-season we did a lot of work on speed," he said. "It's gone down a little bit now, but we still do it once a week.
"We do a lot of work on our movement, lengthening our steps, keeping the knees up, all the technique stuff, and then we do sprint quite a bit.
"We get used to running at that speed three, four, five times in a row, which helps a lot. My times have improved, like everyone else's.
"You definitely want to win.
"TC (Tom Collins), myself and Sleights (Ollie Sleightholme) race a bit more than others and we go at each other to see who comes out on top.
"It's a great asset I have.
"If someone breaks the line, I can be on their shoulder and support them.
"And when I need to break the line and get away from the big boys quickly, it's a huge asset for me."