London Irish head coach Toby Booth was delighted by his side's attitude in their win at Racing Metro in the Heineken Cup on Saturday.
The Exiles recovered from trailing 14-10 at the break to run out 34-14 winners against the French side.
Booth told BBC Berkshire: "You see the true mettle of people in adversity. The players showed how much we care.
"We've come to a club with a bigger budget than us, in a hostile environment, and won convincingly."
Fly-half Adrian Jarvis entered the game after 15 minutes to replace the injured Daniel Bowden, and Booth reserved special words for his performance.
"Coming off the bench as he did is never easy, especially in the pivotal 10 position, so I think he should take a lot of credit," he continued.
"He drove the team around the pitch as we wanted and needed him to do. He was instrumental in that performance."
Irish, who lost their first two Heineken Cup matches, must still realistically win their last three games in Pool 2 to qualify for the knockout rounds, and Booth warned that their opponents would not make it an easy task.
"It depends on what happens in other games next week in particular, and what Racing do after these two fixtures. We've got a very tough game against them again.
"They'll be absolutely devastated to lose at home, and if I was the coach I'd be letting them know.
"I think this was war one. War two is coming next week," he concluded.