Saints shipped five tries as they were beaten 45-14 on Champions Cup opening night at cinch Stadium at Franklin's Gardens.
Saints now face an all or nothing showdown with Ulster in Belfast on Friday, knowing that a defeat will all but eliminate them from the Champions Cup with two pool matches to play.
And skipper Ludlam said: "It's a brilliant opportunity again.
"Europe is an exciting competition.
"Next week is knockout rugby for us. If we don't get a win, our chances are pretty much gone.
"It's an exciting challenge to go there with the odds against us and hopefully put in a performance.
"I said to the team is that it's okay to be disappointed about Friday's game - but what is exciting is that we've got a chance to go and put it right against Ulster.
"We'll come in Monday, learn the lessons and get after Ulster."
Ludlam saw a try harshly chalked off against Racing, but it would only have been a consolation as the game slipped away from Saints during the first half.
They headed in 28-7 down at the break - and there was no way back.
"It was frustrating," Ludlam said. "It was a special opportunity for us to go and really show what we're about.
"Yes, they're a good side but we didn't get our game going and we let ourselves down at times.
"We can say they're a good side but really we've got to be disappointed with how we played.
"Against lesser teams you can switch off at times and find a way back into the game, but a team like that, every time you switch off they're going to punish you for it.
"We switched off way too many times defensively.
"In attack, we were off the ball, we never really put our game on them and got our game going.
"We gave a team like that way too many chances."