SAN FRANCISCO -- Matt Chapman came up with the big hit the A’s so desperately sought. He rescued them again in extra innings. But a bullpen that has struggled to recapture its form from earlier in the season twice denied what could have been a feel-good win.

Chapman’s go-ahead two-run homer with two outs in the seventh felt like Oakland’s hero coming to its aid in a time of need. However, the impact produced by that clutch blast quickly dwindled over the next few innings, ultimately ending with the A’s losing on Saturday night in a 6-5 walk-off loss to the Giants in 10 innings at Oracle Park.

After Chapman put the A’s back ahead in the top of the 10th on a sacrifice fly, Burch Smith gave up the game-tying and go-ahead hits in back-to-back at-bats against Steven Duggar and Curt Casali, with Casali ending it on an RBI double to left.

“It’s frustrating,” A’s manager Bob Melvin said. “After Chappy’s homer, it felt like we were in a good spot to win the game. We had our best guys coming in the game. But they came back and we ended up losing.”

The loss was Oakland’s sixth in its last eight games. Over that stretch, the A’s have been supplanted by the Astros for first place in the American League West, dropping a handful of games in similar fashion to Saturday’s late-inning falter.

An impressive start to the year that saw A’s relievers convert 12 of 13 save opportunities and build a 3.50 ERA through their first 40 games has flipped. Since May 15, the A’s bullpen is 8-for-18 in save chances over 39 games. Saturday’s loss brought two more blown saves, including one by left-hander Jake Diekman after he served up a game-tying homer to Donovan Solano in the eighth.

It would be easy to declare that changes need to be made regarding the bullpen’s back-end usage given the recent woes. But the trio of Diekman, Yusmeiro Petit and Lou Trivino has been an important ingredient to the A’s winning formula for the majority of this season. At this point in the season, wholesale changes to that bullpen strategy do not appear to be in the works.

“Sometimes it’s not perfect, but what’s the alternative?” Melvin asked. “Those are our best guys. Sometimes they’re going to give up some runs. You stick with them until you feel like you need to do something different. It’s easy to say to switch things around, but you have to consider the alternatives.”

Despite the recent skid, the A’s still have reason to be encouraged going forward with the continued resurgence of their star third baseman. Chapman’s two-run blast extended his career-high hitting streak to 14 games, which also currently sits as the longest active streak in the Majors.

During the streak, Chapman is hitting .321 (18-for-56) with five homers, four doubles, a triple and 15 RBIs. The A’s offense had done well to navigate through his early-season slump. But there’s no question that this club is at its best when Chapman is at his best, something he said he’s getting closer and closer to.

“It’s not exactly where I’d like it yet, but the fact that I’m able to drive some balls and take good at-bats feels good,” Chapman said. “A lot of these guys have been carrying the load for a while, so I want to help out and do my part. If I can continue to play well, it’s only going to help our team over this last stretch.”

Regarding the tough stretch of games over the past week, Chapman, an unquestioned team leader, said the mood inside the clubhouse is still calm. Even as they fell to three games back of Houston in the AL West standings, nobody is ready to hit the panic button just yet.

“We’ve played with each other long enough to know that when you play 162 games, there’s going to be stretches where you lose tough games or drop a few in a row,” Chapman said. “Everyone knows that we’re still in a really good spot. The Astros took first place from us, but there’s a lot of baseball to be played. We always seem to finish strong, so we’re in a good spot and everyone is on the same page. We just have to take the loss and come back tomorrow and win.”