Tanner Houck gave up three runs on six hits in 4 1/3 innings, and the Red Sox lost to the Chicago White Sox, 3-2, in the first game of a doubleheader on Sunday in Boston. Steven Senne/Associated Press

BOSTON — Yermín Mercedes opened Chicago’s three-run fourth inning with a long homer, and the White Sox completed a sweep of their split-admission doubleheader against the Boston Red Sox on Sunday with a 5-1 victory.

Nick Madrigal had two hits and drove in two runs for Chicago, which climbed back to .500 at 8-8.

In the opener, Tim Anderson homered on the game’s first pitch and Dallas Keuchel pitched five solid innings in a 3-2 victory.

The teams play the series finale Monday morning in Boston’s annual Patriots’ Day Game, with a scheduled 11:05 a.m. first pitch. Lucas Giolito (1-0, 2.55 ERA) is slated to go for the White Sox against Nathan Eovaldi (2-1, 2.08).

“It’s a body check to get back mentally,” White Sox Manager Tony La Russa said of the early start.

For the first time since the Red Sox started playing their annual Patriots’ Day game in 1959, Monday’s contest will not be in held in conjunction with the Boston Marathon, which was moved to Oct. 11 because of the state’s limits on crowds during the pandemic.

Advertisement

J.D. Martinez had an RBI single for Boston’s lone run in the second game.

Back wearing their traditional white uniforms with red letters and numbers in the nightcap, the Red Sox lost for the third time in four games after their nine-game winning streak.

Mercedes hit a change-up from Martín Pérez (0-1) off the back wall behind the batter’s eye, a drive estimated at 431 feet. Danny Mendick had a bloop RBI single and Madrigal a run-scoring, hustle double to make it 4-0.

“I tried to throw a changeup down and away, but it stayed away in the zone,” Pérez said. “He hit that pitch very good.”

Mercedes enjoyed his first Fenway homer.

“It was really exciting. I’ve never hit a home run in Fenway,” Mercedes said. “I’ve seen a lot of famous players play here.”

Advertisement

Matt Foster (1-1) got five outs for the win in relief of Michael Kopech, who retired the first nine batters but left in the fourth after allowing a walk and a hit.

Chicago’s bullpen went a combined six innings of scoreless relief in the two games.

“I’m telling you, we’re going to have a really good bullpen,” La Russa said.

The Red Sox were held to four hits in the nightcap.

“Stuff-wise, it’s one of the toughest staffs in the big leagues,” Boston Manager Alex Cora said. “They’ve got velo and secondary pitches. They were good.”

Pérez was tagged for four runs and seven hits in 3 2/3 innings.

Advertisement

The Red Sox wore their yellow-and-blue City Series uniforms in the first game for the second straight day, honoring the Marathon with the colors that stretch across the finish line of the famous race.

Yasmani Grandal had an RBI double and Yoán Moncada drove in a run with a single for the White Sox. Keuchel (1-0) gave up two runs and Liam Hendriks got the final three outs for his second save.

Anderson sent a 96.8 mph fastball from Tanner Houck (0-2) into Boston’s bullpen for a quick 1-0 lead.

Kiké Hernández homered around the right-field foul pole for Boston.

THROW OUT THE NUMBERS

Cora jokingly had a simple explanation for why left-hander Martín Pérez was starting the second game instead of the opener.

Advertisement

“We dig into analytics and sabermetrics and all that, we found out that Martín is actually not a morning person, so we decided to go with Tanner,” Cora said, smiling. “I can tell. We had a lot of day games. You didn’t see him walking around the clubhouse a lot.”

TRAINER’S ROOM

Red Sox: Catcher Christian Vázquez was back in the lineup in Game 2 after two games off. … Houck was hit on the lower body by Anderson’s grounder for a single in the fifth. He seemed OK but was pulled for a lefty-lefty matchup. Houck said after that he felt fine.

White Sox: Manager Tony La Russa gave Anderson the second game off because “he was on the bases so much.” Anderson said: “I want to play. I did my homework on the pitcher because I thought he was pitching the first game.”… After the game. La Russa said right-hander Lance Lynn would miss his next scheduled start Wednesday because of something with “his neck, his shoulder,” but he should miss only one.