CHICAGO -- Cubs lefty Shota Imanaga stood on the mound and yelled, soaking in the noise at Wrigley Field after striking out Michael A. Taylor to end the seventh inning on Saturday afternoon. He then slowly walked off the field with some more history in his back pocket.

With another seven scoreless frames for the North Siders in a 1-0 walk-off win over the Pirates, Imanaga lowered his ERA to 0.84 on the season. No pitcher in baseball history has posted a lower mark through their first nine career starts since ERA became an official statistic in 1913.

¡°When you start getting in this territory,¡± Cubs manager Craig Counsell said, ¡°you have to be a little surprised, for sure. We're fortunate to watch it.¡±

Prior to Imanaga¡¯s run out of the gates this season, the lowest ERA through nine career starts (excluding openers) was the 0.91 mark spun by Fernando Valenzuela in his sensational rookie showing for the Dodgers in 1981.

During that Summer of ¡®81, Valenzuela¡¯s performance was quickly dubbed Fernando-mania as he breezed through batters en route to the National League¡¯s Rookie of the Year and Cy Young Awards. Is it still too early to call what is happening on the North Side ¡°Shota-mania?¡±

¡°Obviously I wasn't around for Fernando,¡± Cubs center fielder Cody Bellinger said. ¡°But if it was anything like this, it's pretty tremendous, honestly.¡±

Imanaga¡¯s efforts opposite lefty Bailey Falter, who logged 7 2/3 scoreless innings for Pittsburgh, were rewarded in the ninth.

Christopher Morel sent a pitch from Pirates closer David Bednar into center field. Bellinger -- who doubled in the previous at-bat -- raced home, sliding across the plate to set off an on-field party. Morel flipped his bat as he left the box and threw his helmet high into the air after reaching second base, where he awaited the mob of his teammates.

The Pirates challenged the safe call, which was confirmed after a replay review, allowing the celebration to continue. With the win, the Cubs improved to 8-1 in Imanaga¡¯s outings this season, including a pair of 1-0 wins.

¡°That speaks to it,¡± Counsell said. ¡°It¡¯s hard to win, 1-0.¡±

Imanaga also has the fourth-lowest ERA through a pitcher¡¯s first nine starts of a season in the live-ball era, which traces back to 1920. Ahead of the Cubs lefty on that short list are Jacob deGrom (0.62 ERA in 2021), Juan Marichal (0.69 ERA in 1966) and Zack Greinke (0.82 ERA in 2009).

In Imanaga¡¯s dismantling of the Pirates, the left-hander generated 22 whiffs, which was a single-game high for a Cubs pitcher this season and tied for the fourth-most in a game in MLB this year. It marked the most swinging strikes by a Cubs pitcher since lefty Drew Smyly racked up 23 on Sept. 9, 2022.

Imanaga noted that he was actually battling fatigue throughout his start, explaining why he did not take the hill for the eighth inning with 88 pitches thrown.

¡°I noticed my body was moving a lot better towards the end of the game,¡± Imanaga said via his interpreter, Edwin Stanberry. ¡°Talking about the eighth inning, based on pitch count, I probably could have went out. But based on how I was feeling, how I was feeling some fatigue, it might have been a different story.¡±

Imanaga finished with seven strikeouts, leaning heavily on his deceptive four-seamer (52% of his 88 pitches) and signature splitter (43%). The lefty did not feature a single sweeper, which is typically his third pitch. He created a dozen swinging strikes with his splitter and another 10 with his fastball.

Pittsburgh was held without a hit by Imanaga until the fourth inning, when Edward Olivares snapped that streak by legging out an infield single on a grounder to short. Imanaga carried on, exiting his outing with no earned runs on his line for the sixth time in nine games this season.

¡°This guy¡¯s going to give hitting coaches nightmares,¡± Pirates manager Derek Shelton said of Imanaga. ¡°The fastball¡¯s not 94-95 [mph], but it¡¯s effective. He moves the ball around. The split¡¯s real. It¡¯s strike to ball. The execution of it is really good.¡±

Beyond surpassing Valenzuela¡¯s ERA mark, Imanaga also boasts the fewest walks (nine) through nine career starts (min. 40 innings) for a Cubs pitcher since at least 1901. His 58 strikeouts trail only Kerry Wood (85 in 1998) and Mark Prior (65 in 2002) as the third-most by a Cubs starter through his first nine turns.

¡°If I'm being honest,¡± Imanaga said, ¡°I'm not really too interested in my own stats like that, or any historic value. But just knowing that there are so many good pitchers that came before me ¡­ is a good learning experience.¡±