Peter Kenyon believes Andriy Shevchenko provided value for money during his time at Chelsea.
The Blues chief executive was defending accusations that the recently departed Ukrainian striker had proved to be an expensive flop at Stamford Bridge.
The 31-year-old arrived in England for £30million back in 2006, bringing with him a reputation as Europe's most feared hit-man.
Nine goals in almost 50 appearances would not appear to represent a sound return on the considerable investment paid out by the Londoners, and he has returned to former club AC Milan with a point to prove.
However, Kenyon insists Shevchenko should not be labelled as a failure as he fulfilled his duties at the club.
"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."
Kenyon accepts that some deals turn out better than others, citing the summer signing of Portuguese playmaker Deco as an example of how to bring in quality acquisitions at a sensible price.
"You have to look at these things pragmatically, sometimes these things don't work as well as you want them to," he added.
"Remember, we got Deco for £8million and that looks to be the buy of the season.
"You have got to counter theses things and we are happy with where we are."
