WASHINGTON — The Chicago White Sox were aiming for their first series win since early August.

Instead, they made two errors and gave up a grand slam in the first three innings Wednesday against the Washington Nationals.

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The Sox dropped the series finale 13-3 in front of 23,275 at Nationals Park. Lane Thomas hit the grand slam in the third inning against Jesse Scholtens, giving the Nationals an 8-1 lead.

“We made a couple errors that were costly,” manager Pedro Grifol said. “Other than that, we didn’t pitch very well and we didn’t hit.”

The Sox surrendered three home runs, walked seven and hit two batters on Wednesday. They lost two of three in the series and are a season-worst 37 games under .500 at 58-95. Their last series victory was Aug. 7-9, when they won two of three against the New York Yankees at Guaranteed Rate Field.

Here are three takeaways from Nationals Park.

Michael Kopech got the groundball he needed.

With a runner on third base and one out in the first inning on Wednesday, Joey Meneses hit a grounder to third. Yoán Moncada threw home and caught CJ Abrams in a rundown. But shortstop Tim Anderson couldn’t handle catcher Carlos Pérez’s throw back to third cleanly and Abrams scored on the error.

Kopech bounced back with a strikeout and flyout to wrap up his one inning as the opener.

Kopech said he felt “pretty good, overall.”

“There’s still some adjustments that I know need to be made,” Kopech said. “I was working on a different slider grip and a different approach to my slider and I thought I threw some good ones today. So I think that’s a positive to take away from it.”

Kopech allowed the one unearned run on one hit with the one strikeout. He hit one batter. Nine of his 14 pitches were strikes.

“Strike-throwing is a big part of this game,” Kopech said. “It’s been a big part of what I needed to work on this year. To make even small strides in that is something to be excited about as far as improvement moving forward.”

After making 26 starts, Kopech got some work out of the bullpen. He had three relief appearances before taking the opener role Wednesday.

Grifol described Kopech’s inning on Wednesday as “just OK.”

“His stuff was down a little bit,” Grifol said. “Threw strikes. Had the hit by pitch. Just OK. I don’t think he was strong today, not as strong as he usually is.”

According to MLB Statcast, Kopech’s average four-seam fastball velocity Wednesday was 93.9 mph, while his average for the year is 95.2 mph.

Gregory Santos showed tremendous growth throughout the season, working his way into some situations as a closer.

The right-hander won’t pitch again in 2023 after going on the 15-day injured list Wednesday with right elbow inflammation.

“We’ll just err on the side of caution and shut him down for the rest of the year and let the doctors continue to evaluate him,” Grifol said before Wednesday’s game.

Santos went 2-2 with a 3.39 ERA, five saves and 66 strikeouts in 60 relief outings. Among major-league relief rookies this season, he ranks ranks fourth in appearances, fifth in strikeouts and innings pitched (66 1/3) and 10th in ERA.

“He was probably the seventh or eighth guy in the bullpen and worked his way into leverage slowly,” Grifol said. “At the beginning, he wasn’t pitching in that kind of leverage. He kept performing and performing and had a really good year, a great year.”

While the Sox lost Santos, they regained Garrett Crochet. The Sox reinstated the left-handed reliever after he had been placed on the IL on June 17 with left shoulder inflammation.

Mike Clevinger felt he was on the same page with catcher Yasmani Grandal.

“How we were going to set guys up, how we were going to go around with the patterns the second and third time through,” Clevinger said Monday. “Credit to (Grandal).”

Clevinger went the distance in Monday’s 6-1 victory. He allowed the one run on six hits with seven strikeouts and no walks.

He extended his streak of starts without a walk to four, the longest by a Sox starter since José Quintana also went four straight from June 26 through July 12, 2015.

It was the team’s first complete game since Dylan Cease accomplished the feat on Sept. 3, 2022, against the Minnesota Twins and the first time in a road game for a Sox pitcher since Lucas Giolito on Aug. 21, 2019, at Minnesota.

“What you do hope is that it becomes a competition (for the pitchers) that ‘this is what he did and this is what I want to do next time out,’” Grifol said Tuesday. “And it’s healthy. It’s late in the season for that but it’s always good to see a teammate throw a complete game. It’s a rarity and it’s good to have pitchers that are constantly on me telling me ‘I want to finish that.’

“Cease hasn’t finished one of those (this season) but he’s always talking about it. (Clevinger) is always talking about it, the guys we moved were always talking about it. It was really nice to manage guys who want to start the game and finish it.”