When Harry Redknapp signed Lassana Diarra from Arsenal in January, eyebrows were raised. Why were Portsmouth adding another player to an already overcrowded area of their squad, and why did a promising France midfield player want to leave a club in the big four?

The answers came in Diarra’s outstanding form given regular playing time, which has helped Portsmouth reach Saturday’s FA Cup final against Cardiff City and cemented his place in Raymond Domenech’s France squad for the European Championships. The remaining mystery is why Arsene Wenger, having signed Diarra from Chelsea for £2 million on August 31 last year, did not play him more often.

"For this question you have to talk to Arsene Wenger because every time he put me on the pitch I tried to do my best,” Diarra, 23, said. “For him, I don't know if it was good enough or not, but for me...

“This is why I left: because I wanted more consideration, not just to play every week. When you are in the team and even if you play well the manager doesn't want to put you on the pitch, you have to do something. I didn’t understand it, but I don't think about Arsenal now, I am just focused on Portsmouth."

He took advice from a former team-mate before deciding on a move to Fratton Park. “After I spoke to the manager it was easy, but I also spoke with Frank Lampard at Chelsea and he knows the manager and said it would be a very good move. We have reached the final and that is why I am here.”

But more important than the chance for medals was the opportunity to play. “With the European Championship coming up it was very important for me. France have a very good team and strong squad, but I've played in 11 of the last 12 games. I am in the squad and try to do what the manager says. If he says I play, I play, and if he says I’m on the bench, OK.”

Somehow, Domenech has managed a trick that was beyond Wenger in satisfying Diarra with a place in the pecking order behind Claude Makelele and Patrick Vieira. “Makelele and Patrick Vieira are very big players,” he said. “They are 35 and 32 and if I am not picked I know my time will come.”

His implied criticism of Wenger does not apply to Jose Mourinho, the former Chelsea manager, whom he credits for his confidence. “I was 19 when I signed for Chelsea and I trained with very big players and this is why you feel more comfortable and you believe in your football.

“He was special for me. When I was there he spoke with me … not exactly like my dad, but he explained everything to me. This is why when I am doing well, I think back to some of the words he said to me two or three years ago.

“I remember him telling me when I was at Chelsea: ‘You have the quality so just believe in yourself’. I hope he gets a big team and I wish him good luck. Wenger is Wenger and Mourinho is Mourinho - they are different people. I respect Arsene and Mourinho and I know which one I prefer - but that is for me to know.”