Potentially handed a baptism of fire last weekend in his league debut at Peterborough United, the 19-year-old passed the test with flying colours.
It is likely to ensure that the defender retains his place today even if Daniel Pinillos returns to the fray following injury.
On Williams, who signed a new two-year deal in the summer, Winkler said: “I think everybody was impressed given that he was making his first appearance in League One in a match like this and how he did it. He was fighting and his attitude was terrific.
“Also the longer that the match went he was very composed with the ball and made forward runs, crosses and hard tackles.
“Everyone in the squad helped him. Some players were putting their arms around him directly before the match and saying, ‘Come on, we know you can do it; you do a good job in training and are fighting’.
“He played good matches for the Under-23s, but the squad made it easy for him. He really was very good.”
Winkler believes that the Reds will be able to cope with the absence of influential midfielder Kenny Dougall, a late call-up to the Australia squad at the start of this week.
Dougall had initially been expected to feature for his club today only for the Brisbane-born player to be drafted in as an injury replacement for Huddersfield Town’s Aaron Mooy for this week’s training camp in the United Arab Emirates and the international friendly against Kuwait on Monday.
Called up for a training camp in Turkey at the end of August, former Sparta Rotterdam player Dougall is eyeing a cherished first senior international appearance for the Socceroos.
Winkler added: “It changed our thinking a little bit and we did not really expect it at this moment.
“But he gave me a call and I was instantly happy for him. It is a great thing for him. I never had an international place!
“We have (replacement) players who can play in this position for us or maybe we can change our formation a little bit. We have Alex Mowatt, who is running 12 kilometres every match, so we will find a good line-up.”