Ben Shelton is the first American semi-finalist at the Paris Masters in nine years

Paris (France) (AFP) - World number four Ben Shelton edged out Tommy Paul in an attritional three-set tussle on Friday to book his spot in the semi-finals of the Paris Masters.

A single break of serve in each set was enough to separate the two compatriots as Shelton emerged from the quarter-final battle a 6-4, 4-6, 6-3 winner.

The 24-year-old becomes the first American to reach the last four of the 1000-level event in the French capital since John Isner and eventual champion Jack Sock in 2017.

For world number 14 Paul, the defeat brought not only an end to his hunt for a first Masters title of his career, but also to his hopes of reaching this season’s ATP Finals.

American Frances Tiafoe, who lost in the second round on Wednesday, is now assured of playing in the season finale, which will run from November 15-22 in Turin.

“Frances has had an outstanding year. One of my best friends, and to see him make Turin for the first time is amazing,” Shelton said of the 28-year-old Finals debutant.

On court, Paul was the first to crack when serving at 4-5 as two double faults presented Shelton with set points, the second of which the Atlanta native converted with a forehand winner.

But Paul hit back instantly, breaking Shelton to 15 in the very first game of the second frame.

With his nose ahead, the 29-year-old held firm to serve the match out to a decider.

The momentum swung back in Shelton’s favour in the fourth game as the third seed converted a break point with an inside-out forehand that just nicked the outside of the line.

Shelton then kept Paul at arm’s length to move into the next round, where he will meet Luca Van Assche after the Frenchman ended Australian Rinky Hijikata’s fairytale run from qualifying to the last eight.

On the other side of the draw, seven-time Grand Slam champion Carlos Alcaraz will later take on Taylor Fritz for a spot in the semi-finals.

Former world number two Casper Ruud will close out the day’s play against Portuguese lucky loser Nuno Borges.