Wenger praises midfielder Diaby

Arsenal manager Arsene Wenger is convinced Abou Diaby can become one of the top midfielders in the Barclays Premier League.

Captain Cesc Fabregas is likely to miss tonight's trip to bottom club Portsmouth with a hamstring problem which could sideline him for a couple of weeks.

Diaby has performed well alongside the Spaniard and netted his sixth goal of the season to wrap up a 3-0 win over Aston Villa on Sunday, clearly enjoying his role in the Gunners' new 4-3-3 formation.

Wenger feels the 23-year-old has grown in stature.

"Since the beginning of the season I have always played him when I have the opportunity," the Arsenal manager said.

"He looks to grow with his touch and now he is dominating the fight.

"What is very interesting in this formation is that, in Fabregas and Diaby, you have not one but two players who are good runners, can come out from deep and score goals."

Arsenal will be out to avoid suffering the same fate as Liverpool, who were beaten 2-0 on their trip to the south coast just before Christmas.

Wenger has been full of praise for the way his young side have hauled themselves back into the title race with four wins from five league games.

However, he knows it will be no easy ride at Fratton Park, one of the most intimidating stadiums in the top flight with the fans so close to the action.

It will be a new experience for centre-back Thomas Vermaelen, who has settled quickly alongside William Gallas since his £10million summer move from Ajax.

Wenger believes the mild-mannered Belgian has led by example.

"Thomas is a very quiet boy, but very determined," he said. "I believe you see that in every ball he plays. He is a good mixer with commitment and relaxed focus.

"That is very important when you play at the back, that you never panic, because panic is something which is contagious and he always looks to master that."

Under former Chelsea manager Avram Grant, Pompey have produced some battling displays, notably when going down 2-1 at Stamford Bridge after being just 11 minutes away from a hard-earned point.

However, the defeat to fellow strugglers West Ham has, according to Wenger, made Arsenal's task even more demanding.

"Portsmouth had a defeat on Boxing Day and it was a big disappointment for them," he said. "They were direct competitors with West Ham and they lost.

"But Portsmouth is always a difficult place to go anyway. I watched them against Liverpool and you need to turn up and to come out with a top performance."

Arsenal have lost four times in the Premier League and Wenger accepts the margins for further error are slim to stand any chance of overhauling Chelsea and Manchester United.

"When you are a manager you never think that you can afford a blip, but when we were 11 points behind Chelsea, we definitely could not," he said.

"I still believe that today, but now we are in a position to take advantage of the other teams dropping points."