Chelsea chief executive Peter Kenyon has responded to accusations that Andriy Shevchenko is the biggest transfer flop in Premier League history by insisting the Ukraine striker was a worthwhile investment.

Shevchenko, who cost Chelsea a club record 30 million pounds (37 million euros) in 2006, returned to AC Milan this week after two dismal seasons at Stamford Bridge.

The 31-year-old scored just nine goals but Kenyon is adamant Shevchenko was not a failure.

"I get fed up because it`s not right," he said. "I`m not giving a lesson on accountancy, but you do write money off over the term of a contract.

"What we pay is in an investment. During that period you have a player who is doing a job and in this industry you buy and sell players.

"You have to look at these things pragmatically, sometimes these things don`t work as well as you want them to.

"Remember, we got Deco for eight million pounds and that looks to be the buy of the season.

"You have got to counter these things and we are happy with where we are."