The fly-half was on imperious form in the 42-7 home Rugby Champions Cup victory over GUINNESS PRO12 rivals Treviso on Sunday.
Biggar pulled the strings in the middle of the park all game with Warren Gatland watching on, and punished the visitors in front of the posts with six successful kicks from seven attempts.
And the 25-year-old sees no reason for the Ospreys to back off against a Northampton side who were out of sorts last time out.
"We'll have to front up and be more physical and smarter than we were against Treviso, because we realise how difficult a place it is to play," he told the South Wales Evening Post.
"But we should also go up there with confidence as we are unbeaten at the minute. Yes, we have loads to work on, but why not go up there full of confidence and give it a go?
"If we walk onto the pitch thinking these are the champions of England, Northampton, with all these stars, then there is no point in going there at all.
"For me, it's about going there and giving them a really good run for their money. We are fully expecting to rock up and test them as much as we possibly can.
"We know how they are going to come out of the traps. They're a top side with top players and they are going to be smarting from their defeat against Racing Metro - we are under no illusions that it's going to
be pretty tough.
"But we have a group of boys who are working hard for the club and hard for the shirt. Sometimes that's better than having star boys who sometimes haven't."
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