Victory's stop-start campaign hit a low point with Friday's 2-1 home to Adelaide United, who finished the night with nine men.
With his team languishing in seventh spot with 10 points from 10 games, Muscat - who has led Victory to a championship, premiership, FFA Cup and grand final in his four seasons in charge - is under scrutiny like never before as traverses the final year of his contract.
But Williams, who knows all about setbacks and hardship after bouncing back from career threatening injuries, is adamant Australia's best supported club will not be struggling for much longer.
In a ringing endorsement of Muscat and his methods, Williams - a standout performer in a struggling team - declared: "There is no way we are going to stay down for long, especially with the manager we have, the staff we have and also the players we have.
"It's been a bit hit and miss but ultimately we are still playing OK, but we are just not getting the results.
"It could be worse ... we could be playing badly and not getting the results.
"It didn't help at the start of the season to have so many disruptions but we are all fit and ready to go now and we only have ourselves to blame for Friday night."
Williams doesn't believe Victory are in a rut as they approach Sunday's visit to Brisbane Roar, who share the same number of points as a similar season of inconsistency unfolds.
"With Victory being such a big club people are making a lot of the way things are going at the minute," he added.
"But the manager is great, he's experienced and he's driven and has proven over the years that he's a winner, both as a player and as a coach.
"I am really enjoying playing under him at this great club.
"He won't let us slacken off. Training is fast and the tempo is aggressive.
"We're not a million miles away from where we need to be.
"We haven't been playing rubbish but things just haven't gone our way so far."
While Victory's poor form has shocked some, Williams is more sanguine.
"We drew four in a row, which we thought was OK considering we were missing players and there were away games," he added.
"The win over Perth was great and then we shot ourselves in the foot a week later in losing so heavily to the Jets.
"I got injured in that game and Mark Milligan was sent off as well.
"To bounce back against Wellington the next week was great. But overall we be making it hard for ourselves.
"It's coming though ... ultimately we have to improve."
While Williams, 29, would love to earn a Socceroos recall as he reconstructs a career beset by injuries during his decade at Middlesbrough, he is more concerned with helping Victory climb away from the wrong end of the table.
"Like I've always said, if I'm doing everything I need to do with my club then everything else will fall into place," he added.
"I am quite pleased with the way I am performing, but it's a team game and I would gladly swap some of those performances for points on the board.
"I am playing in a struggling team at the minute and we all need to take that extra step forward and put together some strong performances.
"We have great character at this club. Everybody gets along and even though we haven't been getting the results, everybody is still positive that we can still go on and achieve great things this season.
"We're 10 points off second and there's still a long way to go.
"Where we are now in the table is unusual and that's why people are making a bit of a meal about it.
"We all know in Australia that's it's nice to win the league.
"But ultimately it's down to the finals in this country and bringing your best form to that point of the season."