The Lions are expecting a fierce contest in front of a sold-out crowd of 30,000, with Bay of Plenty a powerful bunch supplemented by 10 players with Super 12 experience.
But the Lions will steer clear of provocation and instead work towards laying down an early marker for their tour of New Zealand.
"It's the first game of the tour and it is their chance to put one over on us," said O'Sullivan.
"We will get hit very hard, very early. We have to be prepared mentally for that and not be shocked or surprised by it.
"The one thing you can say about New Zealand rugby is that it is very physical, very aggressive and in your face. That is the first marker that is thrown down.
"We haven't talked about dust-ups. I don't think we will go with the mindset of getting involved.
"I think discipline is very important and discipline let us down in Cardiff against Argentina. We kept giving away penalty opportunities and Argentina punished us.
"I think that is a good marker for us for the tour. If we are sloppy with our discipline we will get punished. This is a very important game for us."
Responsible for enforcing that discipline will be the likes of vice-captain Lawrence Dallaglio and Richard Hill, both of whom are returning to the international rugby scene for the first time in a year.
While Dallaglio excelled for Wasps having retired from England, Hill spent six months recovering from knee ligament damage.
There were times when Hill doubted making this Lions tour but his prime motivation for making sure it ends victorious can be found in the wreckage of the 2001 campaign.
The turning point of that Test series against Australia came when Hill, who had been immense in keeping George Smith quiet, was struck in the second Test by Nathan Grey's loose elbow.
It was a painful way for Hill's tour to end and he is in New Zealand to make amends.
"Not winning the Test series against Australia means the tour was a failure so it gives those boys who were involved that added desire to win this tour," he said.
"You do not get many opportunities and everyone is excited about taking the field after two and a half weeks of training.
"New Zealand rugby is very physical, in your face and that is the style that is thrown down.
"My motivation is very clear. I want to be an integral part of this team's success."
Hill and Dallaglio will be joined in an imposing back row by Welshman Martyn Williams, player of the 2005 Six Nations.
The Lions have selected some key combinations, with Ben Kay and Paul O'Connell linking up in the second row, while Gavin Henson partners tour captain Brian O'Driscoll in the centres.
Dwayne Peel starts at scrum-half with Josh Lewsey at full-back and Mark Cueto, a late inclusion in the squad following Iain Balshaw's injury, on the opposite wing to Tom Shanklin.
Coach Andy Robinson said: "Lawrence has got the vice-captaincy role and he is leading the pack. He has been in top form and is relishing the opportunity he has been given in the first game.
"It is great to have Hilly back on the international stage. The two young props playing their first games, Gethin Jenkins and Matt Stevens, have got huge roles to play.
"It is great to see the partnership in the second row. I have been very impressed by Paul O'Connell in the lineout and other aspects.
"The back row, with Nugget (Williams) playing with Hill and Lol has a lot of experience and a lot of footballing ability."
Robinson had a warning that for all the Bay of Plenty's expected physical presence, they will expose the Lions if they lose composure at the set-piece and breakdown.
"We have got to show some composure on the ball. We need to have a real effective set piece," said Robinson.
"Most sides we will play against are very good counter-attackers. The Bay of Plenty have some very strong runners there. If we kick poorly and chase badly they will counter against us.
"If we turn the ball over we expect to get killed by that. We must be very alert with the ability to kick well and chase well and not to turn over possession."