What was expected to be a battle between left-handed pitchers Shota Imanaga and Andrew Heaney turned out to be a one-sided affair that saw the Chicago Cubs take a lot of swings without many misses.

Where Imanaga tossed five scoreless innings, Heaney surrendered a pair of two-run home runs. And the bullpen didn’t fare any better, as the Pittsburgh Pirates suffered their biggest blowout loss of the season.

The NL Central-leading Cubs hit four homers in pummeling the Pirates, 9-0, on Tuesday night before 9,434 at PNC Park. The start of the game was delayed 22 minutes because of severe weather.

It was the fifth shutout loss this season for the Pirates (11-19), who dropped their third consecutive game. Their pitching staff allowed 13 hits and five walks without recording a strikeout, making it the first time the Pirates had pitched a game without a strikeout since June 2, 2009, a 3-1 win over the New York Mets.

“It’s very rare,” Pirates manager Derek Shelton said. “You’ve got to credit the Cubs’ approach. The one thing they do is they put the ball in play a ton. We talked about suppressing contact in the pregame with Heaney, but they move the ball all the time. They do a really good job with their approach one through nine, and I think we saw that exemplified.”

Heaney (2-2) was coming off his best performance of the season, allowing one hit with nine strikeouts and no walks in six scoreless innings in a 3-0 win over the Los Angeles Angels on April 23.

He started strong by retiring the first 11 batters, a streak that included Oneil Cruz chasing down a Kyle Tucker fly ball to make a backhand catch at the warning track in left center for the second out in the fourth.

Then Heaney gave up five consecutive hits. Seiya Suzuki doubled to the left-center gap and Carson Kelly followed by sending an 0-1 slider 418 feet to left center for his seventh home run and a 2-0 lead. Michael Busch singled to left but was thrown out by Tommy Pham at second.

The Cubs continued their assault in the fifth when Nico Hoerner hit a leadoff double and Pete Crow-Armstrong smacked a first-pitch fastball 394 feet and into the right field seats for his sixth homer and a 4-0 lead. When Heaney issued back-to-back walks to Tucker and Suzuki to load the bases, Shelton turned to righty reliever Kyle Nicolas, who got Kelly to ground out to second to escape the jam.

“I had some good defense the first three innings,” Heaney said. “You can’t defend homers or walks. I’ve got to do a better job of keeping the ball in play and letting guys make plays for me.”

The Pirates didn’t advance a runner past first base through the first four innings. They finally got to Imanaga with two outs in the fifth, loading the bases with back-to-back singles by Jared Triolo and Isiah Kiner-Falefa followed by a full-count walk from Cruz.

That brought to bat Bryan Reynolds, enduring an 0-for-16 stretch since Thursday. Imanaga threw three split-fingered fastballs in a row, freezing Reynolds with an 83.8-mph offering at the bottom of the zone for a called third strike to end the inning.

“It’s an elite pitch,” Shelton said, “and it looks like he made a pitch.”

Imanaga (3-1) allowed six hits and a walk with three strikeouts but didn’t give up a run, getting 10 whiffs and 12 called strikes.

“He’s been effective against us,” Shelton said. “We got ourselves in a couple situations to be able to score runs and he made pitches. He made pitches on one, they made a nice play on another one and we just couldn’t break through.”

After Andrew McCutchen doubled to start the sixth, Imanaga left the game with leg cramps and was replaced by righty Daniel Palencia. Joey Bart drew a walk and McCutchen advanced to third when Ke’Bryan Hayes lined out to right, but Palencia got Matt Gorski looking at a called third strike and Tommy Pham to ground out to first to keep the Pirates scoreless.

The Cubs added another run in the seventh when Ian Happ doubled off lefty Joey Wentz and scored on Tucker’s single to right for a 5-0 lead. Shelton turned to Hunter Stratton, recalled from Triple-A Indianapolis with Dennis Santana on bereavement leave, only for Suzuki to send his 3-1 fastball 396 feet to center for a two-run homer to make it 7-0.

The Cubs stretched their lead to 8-0 when Dansby Swanson crushed Colin Holderman’s 1-1 sweeper for a 341-foot line drive to left and his fifth homer. In the ninth, Suzuki hit a leadoff triple to the North Side Notch off David Bednar and scored on Kelly’s single for a 9-0 lead.

Suzuki went 3 for 4 with two RBIs and three runs scored, finishing a single shy of hitting for the cycle. Kelly went 3 for 5 with three RBIs, as all nine Cubs starters had a hit.

“You don’t know they’re going to put the ball in play until the ball is out of your hand,” Heaney said. “You have to make good decisions when the ball is in your hand. Make better pitches, I guess.”