Don’t look now, but here comes Petra Kvitova.
Having exited in the second round of both majors since her remarkable return from the knife attack to her dominant left hand, Sunday marked finally the return of the Kvitova of old, downing pre-tournament favourite Garbine Muguruza in straight sets.
If Kvitova pulls off the title – and there’s still a ways to go – it would easily be the most remarkable story in a tournament full of them. After being nearly robbed of her livelihood, the Kvitova of Sunday was as close to her apex as we’ve seen yet, and that’s as scary a proposition for her opponents as it is a heartening ones for her fans.
Read on for our three to see for day 8 at the US Open.
Rafael Nadal (ESP  vs Alexandr Dolgopolov (UKR) – 2nd on Arthur Ashe
A match on paper that should be largely straightforward for Rafa, it’s still hard to shake the feeling he’s in for a tough test. The fourth round was when he exited both Wimbledon and this tournament last year and in Dolgopolov, he faces the exact sort of opponent who can trip him up should he struggle to find fifth gear. Having taken two of their seven encounters, Dolgopolov knows how to cause the Spaniard problems, manipulating rallies by constantly altering pace, only to accelerate out of nowhere and pull some outrageous winners. Of course Nadal has won the other five for a reason, and does a much better job of sustaining pressure and attacking the his opponent’s serve, so it’s hard to bet against Rafa. If there’s one thing to bet on, it’s that three sets or five, it’ll be a match chock full of delectable shotmaking.
CoCo Vandeweghe (USA)  vs Lucie Safarova (CZE) – 3rd on Arthur Ashe
Looking good for a repeat of her semifinal run here a year ago, Vandeweghe now has to clear a major hurdle in the tricky Safarova. Particularly in this matchup, the rankings difference means less than pre-major form to Stan Wawrinka, with Vandeweghe 16 spots higher, but Safarova leading their head-to-head 3-1, having taken the last three matches. If Vandeweghe wants to turn the tables, she’ll have to find a way to break down the Czech’s resolute defence, and keep the ball away from her strong lefty forehand, but that requires a level of consistency the American has struggled to access. Can she do it? Of course – she can out-hit anyone, but Safarova has to be the favourite, and Vandeweghe will need everything the Ashe crowd can give her to get over the top.
Elina Svitolina (UKR)  vs Madison Keys (USA)  – 2nd on Arthur Ashe, Night Session
In a bit of scheduling that is either particularly cruel or thoughtfully adjusted for her new sleep patterns, Madison Keys will once again be taking part in a late-night duel on Ashe – and it’s highly likely to end in similar circumstances. The two have only played once before – New Haven 2015, with Svitolina forced to retire a set and a break down – so there’s neither woman will have much of an edge psychologically, but with her recent triumph in Toronto, Svitolina comes in a slight favourite. If Keys is to pull out the win, she’ll have to dominate the first strike points, and combat the depth of Svitolina’s groundies by taking her massive forehand early and often. Truly it’s a tough one to call, but whoever wins she be in good stead to advance deep into the tournament.