The Brazilian World Cup winner was signed for an undisclosed fee from Atletico Mineiro.

But the 25-year-old required a work permit before he could represent the club - which the club have now acquired.

The midfielder could now make his debut against Liverpool in Sunday's curtain raiser.

But striker Kanu will miss Sunday's match and the Premiership season after twisting his ankle in a pre-season friendly.

The Nigerian international sustained the injury against non-league side Barnet on Tuesday and could be out of action for up to two weeks.

Kanu had looked in good form during the 2-1 victory, scoring Arsenal's first goal before catching his studs in the grass and limping off the field.

Gunners boss Arsene Wenger confirmed the ankle complaint would cause Kanu to miss not only the Liverpool clash but the Premiership opener against Birmingham on 18 August.

It is the latest setback for the Double winners, who have Robert Pires, Freddie Ljungberg and Giovanni van Bronckhorst ruled out with long-term injuries and Francis Jeffers recovering from his latest ankle problem.

"I think Kanu will be missing for the first game of the season," said Wenger.

"Francis Jeffers will be in the group next week but he will not be ready for Sunday. We will be short."

A strong Arsenal side controlled most of the game at Underhill as they finished their programme of pre-season friendlies unbeaten.