Before Saturday, Coco Gauff had never even taken a set off of world No. 1 Iga Swiatek.

Gauff entered their semifinal at the Western & Southern Open in Cincinnati with an 0-7 record against Swiatek, having lost all 14 sets they played.

But with Brad Gilbert now coaching her and urging her from the stands to “be aggressive,” No. 7 Gauff scored the biggest win of her career by taking down the world No. 1 7-6, 3-6, 6-4 to advance to Sunday’s championship match.

Already this summer, Gauff won her first tournament on American soil in Washington. Now she will bid for another against the winner between No. 2 Aryna Sabalenka and French Open runner-up Karolina Muchova.

Gauff’s victory comes nine days before the start of the U.S. Open on Aug. 28 where she hopes to make a deep run.

After splitting the first two sets, Gauff earned a break for 4-3 in the third when Swiatek sailed a two-handed backhand wide.

Gauff then led 40-0 on her serve before Swiatek got it back to deuce. Gauff gutted it out and finally held for 5-3 when the Pole swatted a forehand into the net, causing Gauff to raise her arms and yell, “Come on.”

Serving at 5-4, Gauff earned a match point when Swiatek sailed a forehand long to bring Gauff to 40-15.

Swiatek saved three match points to bring it to deuce.

Finally on the fourth match point, Gilbert shouted to her, “Right here, right now.”

And then she finally won after Swiatek hit an errant forehand volley wide.