Arsene Wenger feels Arsenal must use all of their Champions League experience to get the right result against Porto.
The Gunners have seen their Premier League title hopes rekindled following victory against Liverpool on a night when both leaders Chelsea and Manchester United dropped points.
But Wenger knows a two-legged European tie represents a whole new ball game and no room for another below-par performance.
"The minimum requirement is not to lose the game and be out of the tie," the Gunners boss said.
"A clean sheet will do, but we are team who will not hide - we want to play.
"However, we want to make sure defensively we are okay."
The Gunners have a few injury doubts for the trip to the Estadio do Dragao - a stadium they are yet to win at in the two occasions they have met in this competition.
Andrey Arshavin picked up a hamstring injury in the midweek win over Liverpool and Alex Song is still having trouble shaking off a knee problem.
Wenger accepts the Portuguese club, which Jose Mourinho took all the way in 2004, will be no pushovers.
"From the outside, sometimes you are seen as favourites, but that does not matter," the Frenchman said.
"Porto have been consistently in the Champions League and you know you will get a tough game, so I will not be surprised."
Despite a couple of first-team absentees, the tie could see the return of striker Eduardo who has been hampered by niggling injuries since he battled back to fitness from a broken leg.
"Eduardo has shown signs in training that he is getting sharper again," said Wenger.
"It takes a long time to recover when you have been injured as he was, but he is getting stronger and stronger.
"It is not a worry that he does not score - I told him that, once you start to make assists, it is the same as scoring and that, for me, there is no difference.
"I said the same to Robin van Persie earlier in the season. Don't forget that, at the start of the season, Robin made several assists, but did not score.
"The goals will come - the team gives you back what you give to the team, so it is just a question of patience."