Arsene Wenger has defended Arsenal's lack of summer transfer business.

The Gunners signed only Petr Cech in the recently-closed window to finish the only club in Europe's top five leagues without at least one new outfield player.

Wenger has been criticised for not opening the purse strings yet again but he was quick to guard his club's transfer policy when speaking to reports at he UEFA 2015 Elite Club Coaches Forum in Switzerland.

The Frenchman highlighted Manchester United's decision to pay Monaco£36million for a largely unknown and untried 19-year-old in Anthony Martial as a major reason for not entering the summer transfer market.

"Am I happy with the investment I make? Yes, every time," he said.

"I bought (Alexis) Sanchez, I bought (Mesut) Ozil, I bought Cech, I bought Gabriel last year.

"The problem at the moment is finding the players who guarantee you are a better team after, and that example last night shows you very well."

Wenger added: "It just shows that there are not many players in the world who can strengthen these teams."