Ireland meanwhile made it two wins from two thanks to tries from Chris Henry and Paddy Jackson while Jonny Sexton, who had been on the same side as Warburton as the Lions won the series 2-1 down under last summer, kicked 14 points for the Irish.
Warburton and his side now have two weeks to try and correct their performance with the flanker insisting his side will channel their disappointment into reversing their fortunes at home to France.
"We were definitely outplayed today - the best team won," he told BBC Sport.
"We've still got three games left, we won the championship last time with four wins and that's still achievable this year.
"It was pretty calm, we've got to keep calm. It'll be a real test of character when we've got to bounce back against France in two weeks' time.
"There's not much you can say after a defeat like that. It's a horrendous feeling and we'll use that as fuel for the next game."