The Millers, who have endured an up and down start to the season, posted their best result yet when they won 2-0 at Portman Road.
Warne's side have enjoyed success on the road this season, with previous wins at AFC Wimbledon, Burton and Blackpool and a steely draw at Sunderland, but the boss felt this was their best showing.
They overcame a nervy start, where boss Warne felt they had given a penalty away, to boss the game, with Matt Crooks' double sealing the points.
“In the first 10 minutes, I thought we conceded a penalty, from my angle I was full of anxiety, you always think the worst,” he said.
“But after that, I thought we played quite well and caused a lot of problems. We changed the team, put a bit more energy. We had four full-backs on the pitch.
“We kept a clean sheet, which was great and scored two and possibly could have scored more.
Asked if it was his side’s best away performance this season, Warne said: “Yeah, I think it probably is to be fair.
“We beat Blackpool a couple of weeks ago and I didn’t think we played very well and sometimes you win football matches and you don’t have to play well.
“It’s not like rugby, the best team always wins in rugby but in football you don’t always have to be the best team.
“But I thought tonight was the most all-round performance we’ve had. I think we were poor in parts against Oxford at the weekend.
“I don’t mind losing but it’s just the level of performance I ask for and I asked for a lot tonight in effort and running and I think I got it from all the players so that makes me really proud.”
It was Warne's 150th game in charge of the club, having taken over almost three years ago, and one, as a Norwich fan, he will remember for a while.
"It wasn't a bad way to bring up the 150," he admitted. "I can't ever remember a better away win in those 150 games.
"Having said that, I struggle to remember last week so there might have been one.”