Viktoria Hruncakova and Tereza Mihalikova completed the surprise victory, surviving a late rally by Taylor Townsend and Ashlyn Krueger.

The ATP fines committee handed Tiafoe a penalty of $60,000 for aggravated behavior on top of the maximum on-site fine of $60,000 he got for verbal abuse.

The country's 2010 World Cup hero “felt like a tennis player for a moment,” after competing in his first professional event alongside Federico Coria.

Sinner will be joined in the last four by Taylor Fritz, who rallied from a set down to defeat Alex de Minaur earlier on Thursday.

The 22-time major winner posed for pics and enjoyed his first practice in the host city Thursday.

And if Sinner wins just one set against Daniil Medvedev tonight, Fritz qualifies for the semifinals too.

But problems with consistency and health remain.

One reached new heights, one returned to top-tier form, one retired—and then didn't.

The Aussie is 5-3 in their head-to-head, but he hasn't seen this version of the American.

After struggling with illness in his opening match, the 21-year-old's throwback sports accessory helped him stay alive at the ATP Finals.

But just like the other group, nobody has qualified for the semifinals yet—it all comes down to Thursday and Friday.