Pittsburgh Pirates starting pitcher Paul Skenes delivers during the first inning of Sunday’s baseball game against the Philadelphia Phillies in Philadelphia. Associated Press

PHILADELPHIA — Mick Abel outdueled Paul Skenes to win his major league debut, striking out nine over six innings to lead Philadelphia over the Pittsburgh Pirates 1-0 Sunday for a three-game sweep and the Phillies' 15th win in 20 games.

Brandon Marsh grounded into a run-scoring forceout in the fifth against Skenes (3-5), who pitched a three-hitter with nine strikeouts and one walk in his first complete game in 33 big league starts.

Skenes is 0-3 in his last four starts despite a 2.52 ERA in that span, and his 2.44 ERA this season is fifth among National League pitchers. The top pick in the 2023 amateur draft, Skenes had not pitched a complete game since June 2, 2023, for Louisiana State against Tulane in an NCAA tournament regional game.

Pittsburgh dropped to 3-13 in May and 15-32 this season. The Pirates are 3-6 since manager Derek Shelton was fired and replaced by bench coach Don Kelly.

Abel (1-0), a 23-year-old right-hander selected 15th overall by the Phillies in the 2020 draft, allowed five hits and walked none. The nine strikeouts tied a Phillies high for a debut, set by Curt Simmons against the New York Giants on Sept. 28, 1947.

Abel threw 62 of 84 pitches for strikes. His 33 four-seam fastballs averaged 97.3 mph, and he also threw 22 curveballs, 14 sliders, 11 sinkers and four changeups.

Orion Kerkering, Matt Strahm and Jordan Romano finished a six-hitter, with Romano striking out the side for his fifth save. Before the game, closer José Alvarado was suspended for 80 games following a positive test for external testosterone under Major League Baseball’s drug-testing program.

Singles by Nick Castellanos and Max Kepler starting the fifth put runners on the corners, Alec Bohm flied out and Marsh hit into the forceout. Bryce Harper’s sixth-inning single in the sixth was the only other hit by the Phillies.

Pittsburgh threatened with a walk and a single to start the seventh. Kerkering fielded a sacrifice attempt by Adam Frazier and retired the lead runner at third, then induced a 1-4-3 double play from Isiah Kiner-Falefa.

Skenes pitched the seventh complete game in the major leagues this season.

Mitch Keller (1-5, 4.15 ERA) starts Monday night's Pittsburgh homestand home opener against Cincinnati and LHP Nick Lodolo (3-4, 3.42).