He will be going against a solid player in Tiafoe so let's see if his streak does continue.
I think we can still consider it an upset regardless because the kid is inexperienced and was able to win against Monfils and Tiafoe. But facing against Wawrinka, Sinner melted under pressure, but for sure lots of experience gain in this tournament for him.
So for tennis fans, he will be on the radar for sure, maybe in the next two years his name will be in the top ten so better watch for this kid in the future.