Foster missed several excellent chances in the 1-1 draw four days ago, much to the ire of some sections of the crowd in Durban.
But Williams says the forward has too much quality not to come good and add to his 10 goals in 29 caps as South Africa’s lead forward heading into the 2026 World Cup.
Asked whether he though the criticism would get to Foster, Williams says he expects it only to add motivation.
“Lyle is a big boy. You don’t play in the (English) Premiership for so many years if you don’t have quality. You just have to remind him that you are quality,” said Williams.
“Yes, he is probably in a difficult moment, not only with the national team but with his club team as well. It is a difficult moment for him, and people have to understand that when you watch where his team is at and how difficult it is for him.
“But for him to wake up every day, show up, show faith, try and go again, to miss chances and to look for the next one. He keeps running, he keeps working for the team. That’s all we can ask.
“Eventually, the ball will go into the back of the net because he has got the quality.”
Goalkeeper Williams says he is there as support for Foster if he needs it, but does not think he will.
“I have been trying to keep my eye on him, but it seems like he is okay. I just think he needs that goal to get his confidence back. Strikers like anyone when the ball is back in the net then they are confident," he said.
“Hopefully, if he gets the chances (against Panama), he can bury them, and he can go back to England happy.
“We need a Lyle in good spirits. The country must support him in good and bad moments.”