The 25-year-old American taking the Australian Open by storm says she once chased down Venus Williams to get her autograph

Coco VandewegheCameron Spencer/GettyCoco Vandeweghe is in her first semifinal of a grand slam at the Australian Open.

What a 72 hours it has been for 25-year-old American CoCo Vandeweghe at the Australian Open.

First, she made easy work of world No. 1 Angelique Kerber, 6-2, 6-3, to advance to the quarterfinals. There, on Monday, she dispatched French Open champ and world No. 7 Garbine Muguruza, 6-4, 6-0, to reach her first career grand slam semifinal.

Now, Vandeweghe will play none other than Venus Williams, her childhood idol.

“It’s a dream to play someone you grew up watching,” Vandeweghe said after her quarterfinal victory. “To play an unbelievable player, future Hall of Famer, Venus, to be on the court with her, I’ve only experienced it one time before.

Vandeweghe added that once, as a little girl, she chased Venus around a tournament in California trying to get her autograph.

“I told [Venus] that story one time in Fed Cup when we were on the same team,” Vandeweghe explained. “I said ‘Venus, the first time I asked you for an autograph, I couldn’t get one.'”

Venus’ response, according to Vandeweghe, was almost better.

“She said: “Well, do you want one now?'”

In an Australian Open that has been marked by upsets, no player has stolen the show quite like Vandeweghe. For one thing, she’s charmed the Australian crowds with anecdotes like the one about Williams, interviews about how nervous she has often been — “I guess I play better when I’m nervous and scared” — and, especially, her running on-court dialogue.

“That was just AWFUL!” she yelled at herself recently after an error. “This is like a bad novel!”

Vandeweghe has never been ranked higher than No. 29 in the world, and has only won one WTA title. The power she displayed against Muguruza (including 31 winners) has always been there, though, only now she claims to be in better shape and more committed to tennis than ever before. Part of that is thanks to her new coach, whom she hired after underwhelming stints with former tennis greats Lindsay Davenport and Martina Navratilova.

About that last name — yes, she comes from an impressive family. From ESPN:

Her paternal grandparents were 1952 Miss America Colleen Kay Hutchins and former New York Knick Ernie Vandeweghe. She’s the daughter of former Olympic swimmer Tauna Vandeweghe, and her uncle is former NBA star Kiki VanDeWeghe.

Given her run at this year’s Australian Open, Vandeweghe is not doing too shabby, either. Should Serena Williams beat Johanna Konta on Tuesday, three Americans will be in the final of a grand slam for the first time since 2001.

An all-Williams sisters final would be a throwback, probably the last time we ever see the two compete for a grand slam trophy (Serena is 35, Venus is 36). But Vandeweghe’s presence is just as important — an indication, perhaps, of what’s to come for American tennis.

“It feels really good. It’s amazing to be in a semifinal. But, you know, not satisfying,” she said ahead of her semifinal match. “I want to keep going, keep playing. There’s more things to do out on a tennis court that I’m hoping to achieve.”

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