Irish flanker Sean O'Brien says the historic win over the All Blacks in Chicago last year "counts for nothing" when it comes to the upcoming Lions tour of New Zealand.

And he said an "attacking mindset" would be the key as Warren Gatland's side attempts to become just the second Lions side to win a series in New Zealand.

O'Brien's role on tour will say much about Warren Gatland's tactics - he would offer a more aggressive attacking attitude compared to the likes of Lions captain Sam Warburton, who is regarded as a defensive specialist.

O'Brien missed the Chicago match with injury, returning for the Dublin test where the All Blacks got a measure of revenge for their first ever loss to Ireland.


"That doesn't feed into this system as such," O'Brien told the New Zealand media overnight.

"We played exceptionally well Chicago, but the All Blacks came back at us, so there are lessons to be taken from that too.

"We need to go out there and express ourselves as a Lions group not what has gone before. That Irish win counts for nothing when we go to New Zealand in a few weeks time."

O'Brien has faced the All Blacks five times, and was on the Lions tour of Australia four years ago, when they won the series 2-1. He said getting playing combinations and personalities to gel was the key.

"It's a massive challenge and from what I've learned you have to have unbelievable discipline. And you have to have to play rugby. You can't sit back against the All Blacks and try and soak up pressure. They will kill you.

"You need to out with an attacking mindset and make sure you stay in it moment by can't have lapses of concentration in those big games.

"We had a very strong squad (in Australia four years ago), a good mix of people and players, good combinations of players, and kind of hit the ground running.
"We gelled pretty quickly, got to know each other pretty well. We will need to have that kind of brotherhood straight away."

O'Brien - who is back running after his latest hamstring issue - said the All Blacks would have no trouble finding high quality replacements if leading loose forwards like Kieran Read and Jerome Kaino remained on the injury list. He mentioned the Hurricanes uncapped Brad Shields as one possibility.