Jack Draper celebrates elevation to British number one by reaching semi-finals in Stuttgart

Draper's run in Germany coupled with Cameron Norrie's shock loss to Jack Pinnington Jones in Nottingham means the 22-year-old will top the domestic standings for the first time on Monday.

He will also hit a new career high in the low 30s, potentially enough to earn him a seeding at Wimbledon, after battling to a 5-7 6-4 7-6 (1) victory over American Tiafoe.

Draper will next face Tiafoe's compatriot Brandon Nakashima in his seventh ATP Tour semi-final.

The manner of victory was particularly satisfying for Draper, who lost matches at three successive tournaments on deciding tie-breaks earlier this season but played a superb one this time.

"I'm incredibly happy," he said in an on-court interview broadcast by Sky Sports. "My last three (deciding) tie-breaks, I lost them all, so to come through today was really amazing and I'm really proud of my efforts."

Draper also hit a career-high 31 aces, adding: "I'm really happy with the way I served and the way I played. It was a really high-quality match."

Tiafoe edged an incredibly tight opening set before the pair were forced off court by rain early in the second set.

Draper played a brilliant returning game to break serve at 5-4 after play resumed and put the disappointment of missing a match point at the same stage of the deciding set behind him in a tie-break full of explosive shots.