Cornes has copped heavy criticism, particularly from the Melbourne media, following his sub-par performance against Hawthorn last weekend.
The versatile 30-year-old was shifted to the forward line for the first real time this season and managed just four possessions - his worst return in more than a decade.
Williams dismissed claims the game had gone past the older Cornes brother and said he expected a strong response from the dual All-Australian at AAMI Stadium on Saturday night.
“The fact is that last week was probably Chad’s worst game for the club ever. We sat down and talked about it and he knows it. He’s appreciative of the fact that he’s got another chance to play this week.
“His form in the backline has been okay and at the start of the season it was pretty good. Everyone is entitled to lose some form at some stage. He’s had a wonderful career and he’s been up for a long time.
“With all the credits Chad has earned over the years he’s certainly earned one more game, that’s for sure.”
A highlight of recent games between the Power and Swans has been the match-up of Cornes on dual Brownlow medallist Adam Goodes.
Williams confirmed Cornes would return to his usual position in the backline this weekend, but refused to say whether he would line up on Goodes.
The premiership coach was more forthcoming about the make-up of his forward line, revealing that tall goalkicker Daniel Stewart (ankle) would be replaced in the side by young ruckman Matthew Lobbe.
Port Adelaide has not won a game since losing the club’s greatest-ever goalkicker Warren Tredrea to an ankle injury in round seven and Williams said it would be a challenge to muster a winning score against the Swans.
“It probably looks a little one dimensional (without Stewart, Tredrea and Robbie Gray), so we need to get goals from our midfielders and to share it around,” he said.
“Tredders has been out. Motlop didn’t play for the first six games and Justin Westhoff’s form hasn’t been great. We tried to play Jay Schulz, but he got injured. We tried to play Daniel Stewart and he got injured and then Cameron Hitchcock too.
“In three of the last four games we’ve been in front in the last quarter with a lot of things going wrong. If we can get similar forwards in the forward line working together I’m sure we’re going to get better results.”
The Swans have recalled experienced defender Tadhg Kennelly and new recruit Ben McGlynn for the all-important clash at AAMI Stadium.
Port Adelaide has lost the past five games played between the two teams and Williams said his side would need to match the Swans in contested possessions to end its four-game losing streak.
“Sydney has been an extremely difficult side to beat for us and they’re bringing two quality players in Tadhg Kennelly and Ben McGlynn back into their group… we’re going to have a massive challenge in front of us.”
