PITTSBURGH — Michael Kopech took a beating against the Giants in the White Sox’ home opener, allowing five homers and seven runs.

He knows the Sox need a much better version of that at the back of a starting rotation that overall struggled the first eight weeks of the season. Maintaining much more than one lights-out inning is a must. He expects as much as his stamina builds with each start.

But Kopech liked his stuff, and pitching coach Ethan Katz noted the action and effectiveness of his changeup, a pitch expanding Kopech’s four-pitch mix. That’s what Kopech’s leaning on going into his second start against the Pirates Sunday.

“There were positives from his outing,” Katz said. “With how well he started off, we want him to carry that outing to outing and not lose it in the middle of a game. But something to learn from, he’s working hard in between to get better.”

The Sox suspect the Giants saw something in Kopech’s delivery that tipped his pitch selection.

“There’s suspicion of it,” Kopech said. “I don’t know if there’s anyting to pinpoint or we can know for sure but we looked at some things. We did work on trying to clean that stuff up.

“Just make sure I’m doing the same thing every pitch. But that’s part of the game now. People have technologies for it, they see it. So you have to be almost hyper aware of it without letting it control your thoughts.”

Here are Katz’s thoughts on Kopech coming off a year in which he dealt with knee problems and posted a 3.54 ERA in 24 starts.

“This is the year you want to see him take the next step forward.” Katz said. “Like any younger guy. But this is a great opportunity for him to keep developing. He’s shown a lot of growth in everything we asked in spring training.”

Kopech is confident his pitches will play, but he said he has work ahead in counts and execute pitches better.

“I’m happy with where my stuff is right now,” he said. “Going to keep leaning on that.”

Colas pops first homer

Oscar Colas his his first career homer, in a 13-9 loss to Pirates, against right-hander Wil Crowe in the ninth inning. But the lefty-hitting Colas started the game against lefty Rich Hill.

“Oscar’s not a platoon player,” manager Pedro Grifol said.

“You have to be ready to hit righties and lefties,” said Colas, who was 0-for-3 in his first three plate appearances against lefties. “In a long season, you know if you’re going to do good, you also have to hit lefties.”

Feet first

Luis Robert — and others — have been hurt diving or sliding into bases head first, one reason why the preference from the coaching staff is feet-first slides.

“Just, again, keep these guys in the lineup,” Grifol said. “There’s a lot of injuries that come head first. When it’s time to dive head first, you dive head first. But for the most part if there’s an opportunity to go feet first, just take it.”