Tim Stauffer made his first start in two years Friday. Yet it was Edwin Jackson who looked adrift atop the mound at Petco Park, buried beneath an immediate and rare barrage. Shackled with frequency over these first two months, the Padres erupted for an evening. In an 11-1 thrashing of the Cubs, they snapped a four-game losing streak, pummeling Jackson’s offerings in an unprecedented show of run support. “We haven’t had many of those,” Padres manager Bud Black said. “When that happens there’s a different feeling in the dugout, there’s a different vibe. Guys want to get to the bat rack, they want to start hacking and they want to get involved.” The Padres distributed their dozen hits throughout the lineup, boosting Stauffer in his five innings of two-hit ball, an ideal spot start as Andrew Cashner and Robbie Erlin looked on from the disabled list. Injuries to those arms had accompanied the Padres’ spiral to six games under .500, reached in a series-opening loss to these same Cubs on Thursday. Flash forward 24 hours, and for a little more than three, the Padres cut through the cloud that had descended upon their season. Seven of their first 13 plate appearances resulted in hits, including home runs by Yonder Alonso and Yasmani Grandal. “The hitting,” Alonso said, “was kind of like a snowball. It was just having good at-bats.” The Padres uncorked four runs in the first inning, matching their total over the first three games of the homestand. They piled on with three more scores in the next frame, and for just the second time in Petco Park history, the Padres had produced at least three runs in each of the opening two innings of a game. (They also did it on Aug. 17, 2004, against the Braves.) “That was just what the doctor ordered,” Black said. “It gave Stauff some breathing room.” All this and another run came at the expense of Jackson, who coincidentally was the last pitcher to allow an eight-spot to the Padres. He’d surrendered that in 4 ⅔ innings last April, several months after the Padres pulled out of the bidding for the then-free agent. Friday, the right-hander again proved more helpful from the opposing side, and from the very start. Everth Cabrera led off with a single, Cameron moved him to third with a double and Seth Smith continued his bright-spot May, driving both runners home on a single. Two batters later, Yonder Alonso cracked a meaty fastball over the right-center fence and into “The Beach,” a near-identical two-run blow to the one landed Thursday by former Padres first baseman Anthony Rizzo. In a season disappointingly short on home runs, it was Alonso’s second.