Capello left the Emirates Stadium smiling broadly, agreed that he had been delighted with Walcott's display and that it boded well for the World Cup.
Although Walcott would seem certain to play at the Nou Camp on Tuesday night after the torrid time he gave left-back Maxwell, Arsenal manager Arsene Wenger is still debating whether to use him as an impact player from the bench again.
Rich run of form: Walcott leaves Wolves' George Elokobi on the floor
'He has a chance to start the game but he can as well come on and make a difference,' said Wenger. 'If it's 0-0 with 20 minutes left, you will need players who make a difference.'
Of Walcott's game-changing substitute appearance against Barca, Wenger said: 'It is always difficult to measure whether the impact is just down to the quality of the player or history of the game as well. I must say, I was very, very happy that Theo had such an impact on the game but he had started the game three days before at Birmingham and did not have the same impact.'