Biggar started the game and skippered his country on his 100th Test appearance for Wales.
But the day was to end in huge disappointment for the Saints fly-half.
"This was simply not good enough," said Biggar.
"We have said in the huddle it's probably the last chance for a lot of players."
And Biggar added: "This is the most difficult post-match interview I've ever had to give.
"It was so poor to lose it from where we were. We haven't played well all day, but to not finish it off when they are 70 metres from their own line...
"From the get-go, we weren't quite at it and you get punished. I can't give you a reason why. I don't know what the answer is.
"Too many boys (were) not quite up to speed. We were second in any loose balls and in any balls in the air.
"It's disappointing, something we pride ourselves on that requires no talent, but work ethic - we were well short today and that's got to be looked at very closely."