Ons Jabeur kept Coco Gauff waiting for a top 10 debut as the Tunisian battled past her teenage opponent to reach the Berlin Open final.
Gauff would have secured a career-high ranking on the WTA list if she had won Saturday's semi-final, but top seed Jabeur took it 7-6 (7-4) 6-2 to earn a shot at Belinda Bencic in the title match.
Only world number one Iga Swiatek has won more matches on the WTA Tour than fourth-ranked Jabeur this year, who collected a 29th win as she overcame a 3-1 career head-to-head deficit against Gauff to earn the victory.
Gauff, at 18 years and 98 days, would have become the youngest American to reach a grass-court singles final on tour since Andrea Jaeger was runner-up to Martina Navratilova at Wimbledon in 1983.
It was not to be her day though, Jabeur breaking serve for the fourth time in the match to seal victory, encouraged by a large and vocal Tunisian following.
Reflecting on the match, Jabeur said: "When you play Coco you have to have all the shots. She's a talented player; she's very tough to beat. You can see I've lost already three times against her.
"Sometimes she takes it, sometimes I take it, and it was a great match for both of us."
Ons Jabeur defeated Coco Gauff 76 62 in Berlin to advance to her 2nd career grass-court final.— WTA Insider (@WTA_insider) June 18, 2022
Jabeur has now made the final or better at 4 of her last 6 tournaments (also Charleston (R-UP), Madrid (W), Rome (R-UP). pic.twitter.com/kNn0czx1I9
This is just the second WTA tournament where 27-year-old Jabeur has been a top seed.
"I've tried to act like a number one seed on and off the court, and it's a good pressure," she added. "I'm trying to handle it very well and with the support of our Tunisian people here it's great."
Olympic gold medallist Bencic had earlier claimed an impressive 6-7 (6-8) 6-4 6-4 win over Greek second seed Maria Sakkari in the first semi-final.
Jabeur was bettered by Bencic in a hard-fought Charleston final in April, but is determined to secure a different outcome this time.
"I'm definitely going for the final revenge because we played each other at Charleston, and it was a very, very tough match," Jabeur said. "I hope she's tired from today's match."
Rain meant there was no play at the Birmingham Classic on Saturday, with the semi-finals set back to Sunday.
Beatriz Haddad Maia will face 2019 Wimbledon champion Simona Halep, while Zhang Shuai tackles Sorana Cirstea.