Champions League, first knockout round, second legs/Arsenal (1) v Real Madrid (0), Highbury, 7.45 On TV/Sky Sports 1: For a team with such an elevated reputation, there was remarkable naivety to the Real Madrid display at the Bernabeu two weeks ago.

From the moment when, 82 seconds in, 10 players were stranded up field as Thierry Henry's low through-ball found Jose Antonio Reyes in Iker Casillas's penalty area, they played into Arsenal's hands. Their attacking approach was admirable, but intensely flawed - this time, it seems, their coach, Juan Ramon Lopez Caro, will take more care.

Cicinho, tormented at right back by Reyes, is expected to be dropped in favour of the more defensively minded Michel Salgado.

Needing an away goal to answer Arsenal's, Lopez Caro is also expected to introduce Julio Baptista - the Brazil international Arsene Wenger invested so much time in attempting to secure for himself last summer - to the attack.

With the little Robinho likely to make way for his compatriot, the threat to Arsenal's Champions League progress could be far sterner in their home than in the Bernabeu.

Baptista is known as "the Beast" in his adoptive country and could pose the lightweight Philippe Senderos a problem every bit as significant as Didier Drogba has in scoring three goals in the three games in which the Swiss has played against Chelsea this season.

Arsenal should beware a savvier Madrid, but if Freddie Ljungberg's view is shared by his team-mates, dangerous complacency may have set in.

"If we look at how Madrid have played in the past, they are not as physical as some teams in England," said Ljungberg. "I don't think they can play that type of game."

In football as in the stock market, though, past performance is no indicator of future returns, and a more robust Madrid line-up may test Ljungberg's theory.

Though Lopez Caro, asked six times by the Spanish press about whether Ronaldo would feature, gave no indication of the 11 he will select, the team that played in the weekend's 2-1 win over Atletico Madrid is more suited to tonight's match than was the team that hosted Arsenal.

"We have players who can do things physically, but the most important thing is how we manoeuvre the ball," said Lopez Caro, recognising their lack of fluency last time out.

"We have players who can do things technically and that will be our approach to the game. We have to be more clinical in attack. We will not change our philosophy."

The same applies to Arsenal, who are not expected to modify their approach overmuch from that which worked so well in Spain, and the same selection that won in Madrid is expected again tonight.

"It is about finding the right balance," said Arsene Wenger, who managed to do just that with his own, unexpected, five-man midfield at the Bernabeu.

Flooding the slim Highbury midfield again would seem a useful tactic this evening, though Wenger refused to show his hand.

"I am still not completely decided on that, because Madrid may change their system as well, and we may adapt a little bit to their system. One goal is a good cushion, but also not much of a cushion at all.

"It is just a result which dictates them to have a go at us. You cannot play 90 minutes and think: 'We will just defend that goal' - the lead is just not big enough. As a team we have to defend well because they will have to go forwards and we need a good defensive performance."

Wenger has impressed upon his team that, with so much at stake for two sides whose season's rhythms have been a staccato stutter, complete concentration is essential.

"If you play for 180 minutes it is important that you do not miss five minutes of your game because that can be fatal," he said. "It can help you if the other team does that.

"We are not hang-on specialists. The job is to defend well again against a team like Real Madrid. We want a complete focus on defending well."

It is unlikely that anything less will be enough.