LONDON - When Porto defender Bruno Alves said that Cesc Fabregas is the man his side have to stop if they are to beat Arsenal in the Champions League, he was stating the obvious.

But one of the features of Arsenal's play this season as been the emergence alongside Fabregas of Abou Diaby.

Last week, for instance, in the 1-0 win over Liverpool, Fabregas was subdued, perhaps because of the attentions of Lucas Leiva.

And so it was Diaby, striding forward alongside him, who caught the eye, eventually heading in the winner.

"Diaby for me is the player who is going step-by-step higher and standing really as a strong player," manager Arsène Wenger told the club website this week.

"He missed a complete year with his ankle injury (in 2006-07) and since he came back last year he was out a lot but this year in central midfield he has really stepped up and improved tremendously. He has become a very strong player."

Fabregas is clearly the playmaker but Diaby's physical presence and stamina give Arsenal a balance they have been accused of lacking at times in the past.

This season has brought the 23-year-old six goals in 19 Premier League starts, which has helped cover for the dreadful injuries Arsenal have suffered to forwards this season.

It also highlights the strength of Arsenal's method, their fluidity and their desire to get goals from all over the pitch.

Even if Robin van Persie's injury layoff proves too much to overcome this season, the signs are good for the coming years.

Essentially among the midfield trio, Alex Song defends, Fabregas creates and Diaby provides the bridge between them.

Meanwhile, Bayern Munich and Fiorentina, two teams who appear to be moving in opposite directions, also clash in the Champions League today, with the Bavarians favourites to progress to the last eight. - Sapa-DPA