PHOENIX -- There was no mistaking the magnitude of this Giants-D-backs series.

Both teams lined up their top two starters for the two-game showdown in the desert, with right-handers Alex Cobb and Zac Gallen matching up in Tuesday night’s series opener at Chase Field.

Unfortunately for the Giants, Cobb departed after throwing two pitches in the third inning due to a nagging left hip issue, putting his status for the remainder of the year in question. San Francisco’s season is looking increasingly in jeopardy, as well.

With an 8-4 loss to the D-backs, the Giants slipped further behind the pack in the crowded National League Wild Card race, dealing a significant blow to their playoff hopes with 11 games left to play.

• Games remaining (11): at AZ (1), at LAD (4), vs. SD (3), vs. LAD (3)
• Standings update: The Giants (76-75) fell 3 1/2 games behind the D-backs (80-72) for the second NL Wild Card berth and three games behind the Cubs (79-72) for the third and final spot. They also trail the Marlins (79-73) and the Reds (79-74) in the race. San Francisco and Arizona have split their first 12 meetings this year, meaning the winner of Wednesday’s series finale will also clinch the head-to-head tiebreaker in the standings.

“Nobody’s giving up hope,” said Cobb, who gave up five runs over two-plus innings in his shortest start of the year. “Obviously, you knew you needed to come in here and try to win both. You look around the league and see that other teams kind of took care of business. … It’s a letdown. There’s no other way to really put it. You talk about the highs and lows of the season, when you see the playoff picture get further away from you in a game that you are able to kind of contribute and you don’t, it definitely feels like the lowest part of the season.”

The Giants jumped out to an early lead against Gallen after LaMonte Wade Jr. opened the game with a leadoff triple that got past right fielder Corbin Carroll and scored on Mike Yastrzemski’s sacrifice fly. Joc Pederson made it 2-0 with a towering 425-foot solo shot to center field, but the D-backs pulled within one on Tommy Pham’s RBI groundout in the bottom of the first.

Things went sideways for the Giants in a four-run second inning that featured costly defensive lapses by left fielder Mitch Haniger and third baseman Wilmer Flores. With a runner on first and two outs, Geraldo Perdomo sent a flare down the third-base line that had an expected batting average of .090, but dropped in front of Haniger for a double. Carroll followed with a two-run double to left, putting the D-backs ahead, 3-2.

Did manager Gabe Kapler believe Perdomo’s double was a catchable ball for Haniger?

“I took a look at it after the game,” Kapler said. “He had a long way to go, number one. Number two, our guys had it at about a 20 percent catch probability. On film, it looks like he’s closer to the ball than he probably is. He wasn’t able to get there, and it was a big play in the game.”

After Ketel Marte kept the rally going with a walk, the D-backs attempted a double steal, with the speedy Carroll reaching third base after he kicked catcher Patrick Bailey’s throw out of Flores’ glove. Carroll ended up racing home and slid in safely after Flores made an errant throw to the plate that went over the head of Bailey. The trail runner, Marte, also scored on the play, giving Arizona a 5-2 lead it wouldn’t relinquish.

“I think I caught the ball, and I was trying to be so quick that [Carroll] just kicked it out of my glove,” Flores said. “From there, everything started. But yeah, they’re fast. It’s a play that I should have secured.”

The Giants pushed Cobb’s start back for the second time this month to try to give him more time to recover from the left hip impingement that has bothered him since early June, but the 35-year-old veteran grimaced on several pitches during the fateful second inning and looked visibly in pain after delivering his 52nd and final pitch of the game in the third.

Following a brief mound visit from Kapler and head athletic trainer Dave Groeschner, a dejected Cobb ended up walking off the field and giving way to left-hander Alex Wood.

Cobb has said he doesn’t believe he’ll require surgery to fix the nagging hip issue, but it could be serious enough to shut him down for the rest of the year, especially if the Giants keep fading from the playoff race.

“I’ll have to talk with the trainers and the coaching staff and see what the best route is,” Cobb said. “I’m just more disappointed that I wasn’t able to get through it today.”