This is what was going through Sprem's mind...
I just watched the tiebreak for the first time, and this is what I think was going through Sprem's mind:
"Holy shit. What the fuck just happened? Am I the only one who noticed that? Should I say something? But why isn't anyone else saying anything? And why the HELL isn't Venus doing anything? Did it really even happen? What is going on here? I'm THISCLOSE to the biggest win of my career, playing in my biggest match ever, and what's going on? Fuck, I just made four errors in a row and now Venus has three set points. Focus, Karolina! Oh, Venus is self-destructing, isn't that nice. Wow, I won!"
My point is that Sprem was probably more hurt by the bad call than Venus was because it broke her concentration, whereas Venus didn't notice it. Furthermore, this was the biggest occasion of Sprem's career as she had never played at such a big match on the centre court in front of a packed house and she therefore wasn't experienced enough to really handle the incident. This is the only way to explain why she didn't say anything and made four consecutive errors immediately after the bad call.