"It didn't really seem real, for a moment," said Gauff's father, Corey, between handshakes and slaps on the back and requests for selfies from spectators leaving No. 1 Court. "On the walk to the court, I was walking behind her. She was excited. I was excited. She seemed confident, but I wasn't sure if it was false confidence or she really was. I just said to her: This match is really magical. Just enjoy it. Your first Wimbledon main draw and you're on a main court against somebody you looked up to from the beginning."

It was by far the most anticipated match of Day 1 at the grass-court tournament, but hardly the only upset. Two-time major champion Naomi Osaka, who was No. 1 until a week ago, lost 7-6 (4), 6-2 to Yulia Putinseva, joining two young members of the men's top-10, No. 6 seed Alexander Zverev and No. 7 seed Stefanos Tsitsipas, on the way out.

This one, though, was special, potentially the sort of changing-of-the-guard moment that people could remember for years.

Gauff certainly has the mindset of someone who intends to go far.