Dismissed by pundits before facing Uruguay — with Williams and Benni McCarthy on BBC One both predicting defeat — Cape Verde tore up the script.
A defensive lapse gifted the equaliser, yet Helio Varela still showed real class, taking a delicate touch past the stranded Muslera before calmly slotting home.
Afterward, Cape Verde relied on the defensive resilience that had proved decisive against Spain to see out a point.
They paired that solidity with ambition, however, and kept pushing for a winner.
The display led former South Africa striker McCarthy to say he has a “new lease of respect” for Cape Verde, while ex-Wales defender Williams called it the “most entertaining” game he has covered at this World Cup so far.
“They really came out to play,” said McCarthy. “They were sensational. I thought they were brave.”
“The only thing they need is to refine their final-third entries, find that composure, and make better choices at the death. I think they’ve won a lot of people’s hearts with this performance.”
One Cape Verde fan told BBC Sport at a fan park in the US, “Everybody doubted us, everybody thought we weren’t going to make it. We’re here now.”
That sentiment captures the rising enthusiasm around Cape Verde, who are rapidly becoming one of this World Cup’s standout stories.