SAN DIEGO -- The Giants arrived at Petco Park earlier this week with a prime opportunity to shrink the gap with the Padres in the race for the third National League Wild Card spot. Instead, they’re heading back to San Francisco with even more ground to make up.

With a 13-7 loss in Wednesday’s series finale, the Giants dropped two of three games to the Padres and slipped a season-high 7 1/2 games behind their NL West foes for the league’s final playoff spot.

The Giants’ shaky defense and bullpen were once again exposed as they blew two leads in a wild, back-and-forth affair with the Padres, who erupted for seven runs -- all with two outs -- in the bottom of the sixth inning to turn a tightly contested game into a blowout. San Francisco has now lost 14 of its 20 games since the All-Star break, causing its playoff odds to crater to 3.2 percent entering Wednesday, according to FanGraphs.

“Obviously, if you can come in and you can sweep a team like the Padres on the road, then that puts you in a good position,” manager Gabe Kapler said. “I think it’s an ask that we’re capable of, but it’s probably not the most likely scenario in any given series to go on the road against a very, very good team and come out with three victories. It’s not good enough. We’re not happy with the results here in San Diego. We’re going to keep fighting.”

The Giants jumped out to an early 4-0 lead, but right-hander Jakob Junis couldn’t get out of the third inning in his fourth start since returning from the injured list, surrendering six runs on seven hits while recording only seven outs. Junis opened the bottom of the third by issuing a leadoff walk to No. 9 hitter Austin Nola and giving up a single to Jurickson Profar, setting the table for the heart of San Diego’s order: All-Stars Juan Soto, Manny Machado and Josh Bell.

Soto walked to load the bases with no outs before Machado cut the deficit to 4-2 with a double to left field. Junis couldn’t find a way to stop the bleeding, as he allowed seven consecutive batters to reach base and four runs to score before coaxing a flyout from Ha-Seong Kim for the first out of the inning. He was then pulled in favor of lefty Alex Young, who allowed two inherited runners to score to cap the Padres’ six-run outburst.

Junis emerged as one of the Giants’ best starters in the first half, going 4-1 with a 2.63 ERA over his first nine appearances of the year, but he’s struggled to regain that form since returning from a hamstring strain that sidelined him for over a month. Since coming off the IL, Junis has gone 0-2 with a 7.16 ERA while struggling to find the slider that proved instrumental to his success earlier this year.

“I didn’t throw my best slider today,” Junis said. “I’m still looking for that sharp putaway pitch that I had before the IL. It just hasn’t been there the last couple of starts. Hopefully we’ll keep plugging away and find it between this one and the next one.”

The Giants countered with another three-run rally in the sixth to briefly go back ahead, 7-6, but the shutdown inning once again proved elusive. The Padres responded by stringing together seven consecutive two-out hits -- including a pair of homers by Brandon Drury and Nola -- to score seven runs against relievers Yunior Marte and Jarlín García in the bottom of the sixth and pull away for good.

Poor defense by the Giants played a role in prolonging the rally, as first baseman Brandon Belt made an overthrow to the plate to try to nab Kim after Trent Grisham beat out an infield single. That brought up Nola, who launched a misplaced changeup from García to left field for a two-run shot that stretched the Padres’ lead to 13-7.

San Francisco’s bullpen, which led the Majors with a 2.99 ERA in 2021, now ranks 27th with a 4.45 ERA this year.

“I don’t think it’s a secret,” Kapler said. “For several months, it’s not [been] very good. We can be a whole lot better.”

The Giants will now use Thursday’s off day to try to reset before attempting to get back on track during their upcoming seven-game homestand against the Pirates and D-backs. They’ll have to take care of business against the two sub-.500 clubs to give themselves a chance at catching the Padres, who have won eight of the first 13 meetings between the two clubs this year.

“I just wanted to go out there and try to give the team a chance to win, and I didn’t do that,” Junis said. “The offense came back and took the lead. As a pitching staff, we just couldn’t do it today.”