Leeds went down to a 1-0 defeat against Nottingham Forest in the Premier League, despite creating numerous chances in the opening 45 minutes.
Williams came up against Gnonto, until a reinforcement in the shape of Serge Aurier was brought on at half time, and struggled to contain him.
Newsome thinks that Gnonto had Williams on toast and gave him a torrid 45 minutes.
The former Leeds defender said post match on BBC Radio Leeds: “They made changes at half time. They brought Aurier on at right-back, who did a much better job against Willy Gnonto than Williams had first half.
“I thought Gnonto had Williams on toast first half.
“He absolutely murdered him.”
Leeds only signed Gnonto in the dying hours of transfer deadline day in the summer after missing out on other targets.
Boss Jesse Marsch intended to use the winger in the Under-21s, but soon changed his mind and Gnonto was drafted into the first team, where he is now commanding regular starts.