Melbourne, Australia — Everyone had the same question when the Australian Open draw was revealed: What were the odds that Coco Gauff and Venus Williams would face each other again in the first round at a Grand Slam tournament?

"I was a bit shocked," Gauff said, "I'm sure everyone was a bit shocked."

Gauff, 15, played Williams, 39, to begin her first appearance in the main draw at Melbourne Park, just like they matched up to start things off at Wimbledon about six months ago. And, just like at the All England Club, the youngest woman in the field got the better of the oldest woman in the field, with Gauff beating Williams 7-6 (5), 6-3 on Monday.

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"I definitely was more confident this time. I think I was used to playing on big courts, so the crowd - I guess the size of the crowd didn't startle me as much as last time," Gauff said. "Definitely a bit more positive coming into this match."

Williams is a seven-time Grand Slam winner in the twilight of her career, the Reuters news agency points out.

Gauff was born the year after Williams lost the 2003 Australian Open final to younger sister Serena, Reuters notes. She grew up idolizing the Williams sisters. They've taken home a total of 30 Grand Slam trophies.

It was the most anticipated contest of Day 1 at the first major tennis tournament of the decade, and it didn't disappoint.

The first set, in particular, was intriguing, with Gauff repeatedly pulling ahead, only to have Williams - who already had won four of her seven Grand Slam singles trophies by the time her foe was born - rebuff her.

American Cori "Coco" Gauff reacts during her first round singles match against compatriot Venus Williams at the Australian Open tennis championship in Melbourne, Australia, on January 20, 2020. Dita Alangkara / AP

It wasn't until her fourth set point that Gauff finally pulled it out. She quickly grabbed a 3-0 lead in the second and never let that edge go.

Gauff already has demonstrated all sorts of terrific qualities on a tennis court, from her big, gutsy serves to an ability to track down opponents' shots. Now you can add stick-to-it-iveness to the list.

The match was held in Margaret Court Arena, one of three stadiums with a retractable roof, and that was a good thing. The air quality was fine despite the massive Australian wildfires, but a heavy storm that arrived in the afternoon suspended nine matches on outside courts in progress and postponed more than 20 others entirely, creating a jam-packed schedule for Tuesday.

Gauff said her mission "is to be the greatest. That's my goal, to win as many Grand Slams as possible. … But for today, my mission was to win."

Venus Williams, right, congratulates Cori "Coco" Gauff on winning their first round singles match at the Australian Open tennis championship in Melbourne, Australia, on January 20, 2020. Both are Americans. Dita Alangkara / AP

Gauff is ranked 67th, and Williams, a former No. 1, is 55th. Williams was playing in a Grand Slam tournament's main draw for the 85th time, a record for the professional era, but this also was her first match of 2020, because of a hip injury that sidelined her at the start of January.

This is Gauff's third major, but she sure is precocious.

"She clearly wants it and works very hard and is extremely mature for her age," Williams said. "The sky's the limit for her."