The 21-year-old was believed to be amid a bidding war between Manchester United, Chelsea and Manchester City during the summer but Wenger has admitted that the Gunners could have snapped him up but failed to compete with wage offers from rival clubs.
"The transfer price was fixed, because he had a clause, so everybody was at the same level," said Wenger. "I'm not surprised at all that he goes to Chelsea, and straight away is one of their stars because everybody knew about him.
"Let's not forget that all the big budgets in England were after him. We are not scared to spend the money, but we feel that even if we spend our money, with some clubs we can't compete on certain players."
Meanwhile, the Premier League outfit announced yesterday that they have made a pre-tax profit of £36.3m.