SAN DIEGO (Interstat) — The San Diego Padres stormed into the postseason Sunday, completing a three-game sweep of the Arizona Diamondbacks with a commanding 12-4 victory in their regular-season finale at a sold-out PETCO Park.

Manny Machado keyed a five-run first inning with an RBI single and added a solo home run in the third, setting the tone for an offensive onslaught before a crowd of 45,072. The win gave the Padres a 90-72 final record as they head to Chicago for a National League wild-card series against the Cubs starting Tuesday.

The Diamondbacks, who finished their season 80-82, saw a promising start quickly evaporate. Ketel Marte led off the game by launching his 28th home run of the season to left field, giving Arizona an immediate 1-0 lead.

That advantage was short-lived. The Padres sent 10 batters to the plate in the bottom of the first against Arizona starter Brandon Pfaadt, the losing pitcher. After singles by Fernando Tatis Jr. and Ryan O’Hearn, Machado drove in Tatis with a single to center. Jackson Merrill then laced a two-run double, and Xander Bogaerts capped the rally with a two-run double of his own to put San Diego ahead 5-1. A sacrifice fly by Jake Cronenworth brought home the inning’s final run.

Arizona chipped away in the third inning. A walk to Jordan Lawlar and a single by Geraldo Perdomo set the stage, but the Diamondbacks could only muster one run on a double-play groundout by Tim Tawa, making the score 5-2.

Machado answered immediately for San Diego, leading off the bottom of the third with his 27th homer, a solo shot to left field to restore the four-run cushion.

The Padres broke the game open with a three-run fifth inning, capitalizing on a defensive miscue. After Bryce Johnson was hit by a pitch, O’Hearn reached on a fielding error by first baseman Tawa. Will Wagner followed with a single to load the bases, and Merrill delivered again, smashing a two-run double. A fielder’s choice by Gavin Sheets brought in another run, pushing the lead to 9-2.

San Diego added three more in the seventh. A single by Cronenworth scored Merrill, and Jose Iglesias cleared the bases with a two-run double, extending the lead to 12-2.

Arizona scored two unearned runs in the ninth on a fielding error by O’Hearn, but James McCann grounded into a game-ending double play.

The winning pitcher was JP Sears, who improved to 9-11. He worked 5 2/3 innings, allowing two runs on seven hits while striking out four. Pfaadt took the loss, falling to 13-9 after being charged with six runs on six hits in just three innings of work.

Beyond Machado’s two-hit, two-RBI day, Merrill was a standout for the Padres, going 2 for 3 with a walk, two doubles, three RBIs and three runs scored. The San Diego bullpen was dominant, with Bradgley Rodriguez striking out all three batters he faced in 1 1/3 perfect innings.

For Arizona, Marte’s leadoff homer was a highlight in an otherwise frustrating afternoon that saw the Diamondbacks strand multiple runners and hit into two double plays. Alek Thomas had two doubles in the loss.

The Padres now turn their attention to the Cubs, with whom they split the six-game season series 3-3. This will be the first postseason meeting between the franchises since the 1984 NL Championship Series, which San Diego won in five games. The Padres are a perfect 3-0 all-time in wild-card series but will have to overcome a 38-43 road record this season.

The game, which lasted 3 hours and 11 minutes, was played partly in the afternoon and concluded in the evening. The total of 16 runs surpassed the pregame over/under line of 8, defying the projection of a 7-6 Padres victory from Interstat’s game simulator.