PITTSBURGH — Pirates ace Paul Skenes struck out nine over six solid innings in a win Monday to bring his strikeout total for the year to 151, a franchise record for a rookie.

The 22-year-old Skenes (10-2) allowed one run on six hits in the 3-2 win over the Miami Marlins, lowering his ERA to 2.10. The 6-foot-6 right-hander’s fastball hit 100 mph six times while becoming just the fourth rookie ever to reach 150 strikeouts in 20 starts or less, joining Kerry Wood, Dwight Gooden and Mark Prior.

Cy Blanton in 1935 previously held the record for most strikeouts by a Pirates rookie.

“I think that just goes to the quality of his stuff,” Pirates manager Derek Shelton said. “This kid’s got elite stuff, and he’s going to strike out a lot of people throughout his career.”

While Skenes wasn’t particularly efficient — he needed 98 pitches to record 18 outs and retired Miami in order just once — he was able to avoid major trouble to bolster his bid for National League Rookie of the Year.

Skenes’ rapid rise has been one of the bright spots for the Pirates, who saw their hopes of staying in the postseason mix die during a miserable August.

While the team around him has scuffled, Skenes has kept right on going. Though his velocity has dipped slightly since his electrifying debut, he started to lean a little heavier on a repertoire that includes a “splinker” (a mix of a sinker and a splitter), designed to keep hitters off balance. He used a handful of different types of pitches to record a strikeout against Miami.

When he retired Marlins rookie Griffin Conine on a grounder to first to end the sixth, the thin mid-September crowd at PNC Park rose to its feet to laud Skenes in one of his final home starts of the season.

“That’s pretty dang cool every time,” Skenes said. “So, yeah, just keep showing up for the games. And hopefully, I mean, the goal is to keep giving them moments like that.”

Pittsburgh has been spacing out Skenes’ appearances to help him get through his first full year as a professional healthy. The Pirates will finish a nine-game homestand with three against the Kansas City Royals over the weekend. Skenes could potentially start the finale.

While Skenes allowed there “probably is a limit” to the number of innings he pitches this year — he’s at 147⅓ innings all told between Triple-A and the majors — he doesn’t think he’s going to reach it this year. Besides, he also thinks he’s built to withstand the workload.

“I’m 22, I’m conditioned to throw a lot of innings I think,” he said.

The Associated Press contributed to this story.