The Wales star delivered some telling contributions during the second half, notably setting up tries for Cobus Reinach and George Furbank as Saints beat Lyon 36-24.
It was the black, green and gold's first win on French soil since January 2011, ending a run of 11 successive defeats across the Channel.
And it was also Biggar's first taste of Champions Cup success in France.
"It was a really good win," said the former Ospreys fly-half.
"It's actually my first win in the Champions Cup in France - I'd never won over there.
"I'm really pleased for us as a club because we put a lot of effort into the past couple of weeks.
"We know we didn't quite get things right in terms of our performance against Benetton but we did enough to get a result and it was really pleasing that in two games we had to get nine or 10 points from to stand a chance, we've delivered in any way, shape or form.
"There was a lot of good stuff on Saturday, there's obviously still lots to work on but it was a really great result.
"We can be pleased with our efforts over the past couple of weeks."
Saints bounced back brilliantly from a 17-5 half-time deficit to beat already-eliminated Lyon and earn a place in the Champions Cup quarter-finals, where they will meet Exeter Chiefs.
And Biggar added: "We were a little bit unlucky to be 17-5 down because I thought we left some tries out there.
"But we also knew we were under a fair bit of pressure and their physicality was causing us a fair few problems.
"We couldn't quite muscle our way back into the game in the first half, but we spoke really calmly at half-time.
"We focused on three or four things we had to get better at rather than making wholelsale changes and tearing up the playbook.
"We knew there were a few things we needed to improve on and it was a real positive in terms of how well the coaches spoke at half-time.
"We just managed to apply a bit more pressure by holding the ball and playing in the right areas in that second half."