One of the interesting subplots in the build up to tonight's Champions League clash between Arsenal and Napoli has been the cordial relationship between Arsene Wenger and Rafa Benitez.

Both have been effusive in their praise of each other with Benitez calling Wenger the best manager in the Premier League and the Frenchman claiming that his Spanish counterpart was harshly treated by Chelsea fans.

Any amicable relations will have to be put on the backburner though.

Arsenal and Napoli will both fancy their chances of making it to the Champions League knockout stages. But with last year's finalists Borussia Dortmund hovering menacingly behind them, both Wenger and Benitez know that a victory tonight will be crucial and defeat unthinkable.

Benitez has started off very well this season, winning five from six in Serie A and beating Dortmund in the opening group game.

Napoli were already a rising force in Italian football over the last 2 - 3 years but with Rafa at the helm and astute signings like Gonzalo Higuain, Raul Albiol, Pepe Reina and Jose Callejon they may have become less one dimensional.

Certainly, the formation has changed from last season. Napoli had become well known for using a back three with advanced full backs in Juan Zuniga and Christian Maggio under Walter Mazzarri, but Benitez has reverted to a back four and a less radical 4-2-3-1.

But they have added extra frills as their pass completion is up compared to last season.

Whereas they were more of a counter-attacking unit last season, they have yet to score a goal on the break this season.

But that does not mean they cannot break quickly if Arsenal lose possession in dangerous areas due to the pace and incisiveness of the advanced quartet made up of homegrown winger Lorenzo Insigne, Jose Callejon, Gonzalo Higuain (a doubt for tonight's game) and attacking midfielder Marek Hamsik who provides a goal threat from range and thanks to his runs into the box.

That pace on the break is something Wenger has already highlighted, emphasizing the need for the Gunners to be aware of transitioning quickly between attack and defence.

The runs of left wing back Zuniga should also be tracked, given his propensity to attack. For example if you look at his average positions on the left side of the pitch in the 2 - 1 win against Milan, the Colombian spent more time in the opposition half than he did in his own half.

This is aided by Insigne's willingness to cut inside and provide space for Zuniga to run into.

While Hamsik is a goal threat, having scored four goals in five games (he is their top scorer in Serie A), his very varied movement in the opposition half is a hallmark of his play. For example, against Milan he spent 18 per cent of the match in the attacking midfield zone, 11 per cent in the box, 20 per cent on the left wing, 18 per cent in the centre circle and a similar amount of time in front of his own box. Tracking his runs will be key for Arsenal and they should note that he has a tendency to drift towards the left side of the pitch.