German Michael Skibbe was criticised for buying a player with a known history of injuries.
But the 29 year old is proving the doubters wrong.
Entering the Turkish Super Kupa final last weekend as a substitute, he scored one goal and set up another in the 2-1 defeat of Kayseri.
Then in Galatasaray's first Super Lig match of the season the Socceroo scored the opening goal in a 4-1 victory over Denizlospor.
"When we did Kewell's transfer, a number of people criticised us a lot," Skibbe said. "But he showed us what he can do and what he is capable of doing. Those who criticised when we got Kewell should talk now. I'd be curious to hear what they have to say."