No-one has risen more swiftly up the ranks in women's tennis this season than Aryna Sabalenka, and the Belarusian is looking to do some damage in New York.
Sabalenka began the season ranked 78 but now sits just inside the top 20 and, at 20, is the youngest of that elite group.
She began to make a name for herself during Belarus' run to the Fed Cup final last season but it is this summer where she has really hit the big time, reaching the third round in Montreal, the semi-finals in Cincinnati and then winning her first title in New Haven last weekend.
She took four top-10 scalps during that sequence and, after defeating Vera Zvonareva 6-3 7-6 (9/7) to reach the third round at a grand slam for the first time, Sabalenka said:
"Of course this is unbelievable for me and I'm really in shock right now because it was such a great summer for me.
"I didn't expect it to be that good and I'm so happy with this level I show on the court."
The biggest question mark heading into the tournament appeared to be whether Sabalenka would have the stamina for another deep run, but that does not seem an issue given she promptly headed straight back out to the practice courts.
"Actually I'm OK," she said. "I thought I would be so tired at the US Open but, touch wood, I'm feeling really good right now and I hope I can keep it until the end."
The third round is usually where grand slams come alive and there will certainly be plenty of eyes on Sabalenka's next clash with fifth seed Petra Kvitova, who is showing strong form in New York and defeated China's Wang Yafan 7-5 6-3.
The pair have met once before, in Miami earlier this year, when Kvitova won in three close sets.
The Czech said: "Definitely she's on fire right now and in great form. I think that we are playing a little bit of a similar game. I'm going to try to be the one who puts the pressure on her."
Wimbledon champion Angelique Kerber survived a lengthy tussle with Swede Johanna Larsson.
The German looked to be cruising at a set and a break up and served for the match only for Larsson to hit back and take it to a decider, which fourth seed Kerber edged for a 6-2 5-7 6-4 triumph.
Sixth seed Caroline Garcia was also pushed hard in a 6-2 1-6 6-4 victory over Monica Puig but Naomi Osaka needed just 50 minutes to defeat Julia Glushko 6-2 6-0.
Eleventh seed Daria Kasatkina was beaten, though, the Wimbledon quarter-finalist falling 6-2 7-6 (7/3) to Aliaksandra Sasnovich.