​SAN DIEGO — The Chicago Cubs must quickly move past an all-around bad showing to extend their season.Their postseason turned into a nightmare almost immediately in the Cubs’ 8-0 loss in which they were held to three hits during Game 1 of the wild-card series Tuesday night against the San Diego Padres at Petco Park.Matthew Boyd typically doesn’t go to his changeup to open a game. The veteran left-hander’s second-most-used pitch helps counter his fastball, especially to right-handed hitters. Boyd had not thrown a first-pitch changeup to begin a start in 56 games, dating to Game 3 of the 2024 American League Championship Series, when he delivered one to Fernando Tatís Jr. in the bottom of the first inning.Tatís seemed ready for it, crushing a 405-foot first-pitch home run to set off a frenzy among the 47,084 fans. Two batters later, Manny Machado didn’t miss his 0-1 changeup, going deep for a 2-0 Padres lead. Tatís and Machado teamed up again in the third when Machado’s RBI double off the right-center field wall scored Tatís, who had walked.While the Padres kept ambushing Boyd’s changeup, the Cubs went 6 1/3 innings before managing a hit off Michael King on Nico Hoerner’s infield single down the third-base line. They didn’t tally another until Seiya Suzuki’s one-out single in the ninth.The Padres completed a trifecta against Boyd when Xander Bogaerts homered off another changeup in the fourth inning to put the Cubs in a four-run hole. Boyd had surrendered six home runs off his changeup (546 thrown) in the regular season. He had suppressed the long ball in September, not allowing a home run in five starts spanning 29 2/3 innings.The early four-run deficit felt even bigger with King cruising against the Cubs. They had a chance to cut into the Padres’ lead in the second and third innings with a runner in scoring position in each frame, but failed to come through. The Cubs didn’t put a runner past second base after Pete Crow-Armstrong swiped second in the third inning.San Diego kept tacking on against the bullpen. Jackson Merrill’s bases-loaded two-run single off lefty Ryan Rolison, followed by catcher Carson Kelly’s passed ball, resulted in a three-run fifth inning. The lack of crispness extended to the defensive side when Kelly’s throw to shortstop Dansby Swanson on Tatís’ steal in the seventh skipped into left field. The throwing error allowed Tatís to score from second, easily beating Ian Happ’s throw home.The Cubs did not have many options to start Game 1 when they ultimately settled on Boyd, who finished with four runs allowed on five hits, one walk and struck out four.Right-hander Kevin Gausman appeared lined up to get the ball Tuesday night, but a freak injury to his left shoulder on a diving tag in his final regular-season start last Wednesday seemingly thwarted that plan. His shoulder didn’t feel great in the ensuing days, and his pregame bullpen Tuesday went well enough that Gausman will be starting G