CHICAGO (Interstat) — Dansby Swanson hit three home runs, including a grand slam, and drove in eight runs as the Chicago Cubs routed the San Diego Padres 23-3 Wednesday afternoon at Wrigley Field.

The Cubs completed a three-game series sweep and extended their winning streak to four games, improving to 49-38. San Diego fell to 43-42 for its fourth consecutive defeat.

Swanson homered in the second inning off Padres starter Walker Buehler, then struck again in the third with a three-run shot off the same pitcher. His grand slam in the eighth inning off reliever Stephen Hall capped an eight-run outburst that pushed the lead to 22-3.

The most important part of the game occurred in the bottom of the third inning. After the Cubs had taken a 4-3 lead on Swanson’s solo homer in the second, they broke the game open with a five-run frame. With one out, Seiya Suzuki walked and Ian Happ doubled to put runners at second and third. Buehler intentionally walked Michael Conforto to load the bases. Miguel Amaya then singled to center, driving in Suzuki and Happ to make it 6-3. Swanson followed with his second home run of the afternoon, a fly ball to center field that scored Conforto and Amaya, extending the lead to 9-3.

The Padres never recovered. San Diego manager Mike Shildt pulled Buehler after the third inning. Buehler allowed nine runs on five hits and five walks over three innings, striking out four. He took the loss, dropping to 5-4.

Colin Rea earned the win for Chicago, improving to 6-5. He pitched five innings, allowing six hits and two earned runs while striking out five. Jordan Wicks recorded his second save of the season with three innings of relief, surrendering five hits and one earned run with two strikeouts.

The Cubs’ offensive onslaught continued throughout the afternoon. After scoring three runs in the first inning on a Suzuki home run, they added one in the second, five in the third, four in the fifth, two in the sixth and eight in the eighth.

Suzuki’s first-inning blast traveled to center field and scored Pete Crow-Armstrong and Alex Bregman, giving Chicago an early 3-0 lead. Crow-Armstrong led off the game with a single and Bregman walked. Suzuki’s 13th home run of the season came on a full count.

In the fifth, Conforto homered to center, his sixth of the year, pushing the lead to 10-3. Later in the inning, Crow-Armstrong hit a three-run shot, his 19th, to make it 13-3.

Conforto finished 3-for-4 with two home runs and four RBIs. He also had a two-run homer in the sixth inning, his seventh. Michael Busch added a solo home run in the eighth, his 11th, to make it 23-3.

Amaya went 2-for-4 with three RBIs. Crow-Armstrong was 2-for-4 with a home run and three RBIs. Suzuki doubled and had two hits and three RBIs.

The Padres’ offense was limited to 11 hits. They scored two runs in the fifth inning on a solo home run by Sung-Mun Song, his first of the season, and a ground-rule double by Ty France that scored Manny Machado. In the eighth, Samad Taylor tripled and scored on a Miguel Andujar single.

San Diego managed only one hit through the first four innings against Rea. The Padres left seven runners on base and grounded into two double plays.

The Cubs’ 17 hits included three home runs from Swanson, two from Conforto and one each from Suzuki, Crow-Armstrong and Busch. Swanson’s grand slam in the eighth was the highlight. With the bases loaded and one out, he drove a 1-2 pitch from Hall to left-center field, clearing the bases and giving the Cubs a 22-3 lead. The home run was his 16th of the season.

Chicago’s defense was solid, turning two double plays. The Cubs also received a strong outing from their bullpen after Rea departed.

The game drew 37,311 fans to Wrigley Field and lasted 2 hours, 37 minutes.

San Diego heads to Los Angeles for a four-game series against the Dodgers starting Thursday. The Cubs host the St. Louis Cardinals for a three-game set beginning Friday.

The total score of 26 runs went under the over/under line of 11.5 set by oddsmakers. Chicago had been installed as a pregame favorite with a spread of minus 1.5 runs. Interstat’s game simulator had projected a final score of Chicago Cubs 7, San Diego Padres 5, and Interstat’s ELO system had given the Cubs a 55.40 percent probability to win.