PORTO: Arsene Wenger says Arsenal will marry caution with adventure when they visit Porto for the first leg of their Champions League last 16 tie here on Wednesday.

The Gunners returned to league form with a much-needed 1-0 win at home to Liverpool in their last outing following damaging back-to-back defeats against title rivals Manchester United and Chelsea.

Victory over Rafael Benitez?s side took Arsenal to within six points of league leaders Chelsea and they have had a full week to prepare for the trip to Portugal due to their early elimination from the FA Cup.

Arsenal, though, have not won on their previous two visits to the Estadio do Dragao and Wenger believes his side must approach the game carefully.

"The minimum requirement is not to lose the game and be out of the tie," said the Arsenal coach.

"A clean sheet will do, but we are a team who will not hide - we want to play. However, we want to make sure defensively we are OK."

The Londoners? cause has not been helped by injuries to influential players.

Dutch international striker Robin van Persie has already been ruled out for much of the season with an ankle injury and Russian playmaker Andrey Arshavin is unlikely to feature against Porto due to a hamstring problem.

Defensive midfielder Alex Song is also a doubt with a knee ligament injury, but Croatian striker Eduardo (hamstring) and France midfielder Samir Nasri (head injury) are expected to be fit.

Eduardo has not been prolific in front of goal this season but Wenger is backing him to come good as he continues to adapt to top-level football after a year out with a badly broken left leg.

"Eduardo has shown signs in training that he is getting sharper again," Wenger said.

"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."

Porto have made it through to the Champions League knockout phase six times in the last seven years, winning the competition in 2004, and Wenger anticipates a tight tie.

"From the outside, sometimes you are seen as favourites, but that does not matter," said the Frenchman, whose side reached the semi-finals last season.

"Porto have been consistently in the Champions League and you know you will get a tough game, so I will not be surprised."

The reigning Portuguese champions have demonstrated a rich pedigree in European competition in recent years but they are much changed from the side that frightened eventual runners-up Manchester United in last season?s quarter-finals.

A summer of upheaval saw Argentine pair Lucho Gonzalez and Lisandro Lopez as well as left-back Aly Cissokho leave for France, with playmaker Lucho joining Marseille and striker Lisandro linking up with Cissokho at Lyon.

Jesualdo Ferreira?s team are currently nine points behind Portuguese league leaders Benfica with a game in hand, having been held to an underwhelming goalless draw at second-bottom club Leixoes on Saturday that sparked clashes between angry Porto fans and police.

"To be realistic, we have to fight against the bigger powers in Europe, with different budgets, with a different type of players of a different level," said Porto defender and captain Bruno Alves.

"But I think in football that's not everything. It's a matter of showing who's stronger on the pitch, plays better, scores goals. We've always had good campaigns in the Champions League and I always think we can win."