SAN FRANCISCO -- The Giants passed a huge test by taking three out of four games from the Dodgers during a dramatic showdown at Los Angeles earlier this week, but it didn’t take long for them to turn the page and begin preparing for their next series against the Pirates.

Even while they were fresh off the high of staging back-to-back, ninth-inning comebacks against Dodgers closer Kenley Jansen, manager Gabe Kapler made a point to remind the Giants that it was important to maintain that same level of intensity against the last-place Pirates.

“We’ve got to remember that this is a good baseball team, independent of record,” Kapler said before the game. “You just can’t let off the gas at all.”

Despite the messaging, the Giants couldn’t avoid an emotional letdown, as a disastrous seventh inning ultimately doomed them in a 6-4 loss to the Pirates in Friday night’s series opener at Oracle Park.

“What’s frustrating is I don’t really think [we played] our best game from any angle,” Kapler said. “I don’t think we played our best offensive game. I think we were kind of uncharacteristically out of the strike zone a bit. I don’t think we defended our positions the way we’re capable of. It’s hard to win a baseball game when you’re not at your best in those three components of the game.”

Alex Dickerson launched a two-run homer off Pittsburgh right-hander Chad Kuhl to tie the game, 3-3, in the bottom of the sixth, but the Pirates quickly regained the lead by rallying for three runs in a sloppy seventh by the Giants.

Dominic Leone, who entered Friday with a 1.29 ERA over 21 appearances for San Francisco this year, opened the fateful inning by issuing a leadoff walk to Jacob Stallings. Kevin Newman followed with a fielder’s choice grounder to shortstop Thairo Estrada, but with the hit-and-run on, Stallings managed to beat Estrada’s throw to second. Donovan Solano’s relay throw to first was also too late to get Newman, putting a pair of runners on with no outs for the Pirates.

Kapler said he felt Estrada, who is filling in for the injured Brandon Crawford, would have been best served by throwing to first to ensure that at least one out was recorded on the play.

Instead, the situation continued to unravel as Leone struggled to find the strike zone. Back-to-back walks to pinch-hitter Wilmer Difo and Adam Frazier put the Pirates ahead, 4-3, though the Giants came close to limiting the damage to one run after left-hander Jarlín García appeared to induce an inning-ending grounder from Ben Gamel.

First baseman LaMonte Wade Jr. fielded the ball and tried to flip to García, but he fumbled the exchange and dropped the ball, allowing Gamel to reach on an error. Two more runs scored on the misplay, extending the Pirates' lead to 6-3. Pittsburgh didn’t produce a single hit in the seventh, making the Giants’ mistakes particularly galling.

“I think LaMonte had some time there,” Kapler said. “He’s been so good for us at first base, so instinctive, so quick. In this particular case, I think he had a little bit more time than he realized and fumbled with it a little bit and wasn’t able to complete the play. I know it was especially frustrating for LaMonte because he demands so much of himself. He’s a human being and everyone is going to make an error from time to time.”

Wade atoned for his error in the bottom of the ninth, delivering a two-out RBI triple to bring the potential tying run to the plate, but Pirates closer Richard Rodríguez struck out Mike Yastrzemski looking to end the game.

“I think the fans need to understand that you’re going to win some and you’re going to lose some,” said veteran right-hander Johnny Cueto, who didn’t factor into the decision after giving up three runs over five innings. “But I think the guys were maybe a bit tired because they arrived late last night. It’s baseball. We’re going to stay strong and turn the page on this one.”

The Giants outhit the Pirates, 8-4, but they looked flat at times against Kuhl, who recorded his first six outs of the game via strikeout.

San Francisco finally got on the board in the third, when Steven Duggar drove a hanging slider from Kuhl into McCovey Cove for his seventh home run of the year and his first since June 16. Earlier in the at-bat, Duggar appeared to tweak his side on a swing, but he stayed in the game and asserted his health with the splash hit two pitches later.

Cueto kept the Giants’ third-inning rally going by drawing a walk and advancing to second on the first stolen base of his 14-year career, but the Giants left him stranded after Kuhl struck out Wade and Yastrzemski and retired Buster Posey on a groundout.

“I always joke with our first-base coach [Antoan Richardson] and tell him that I’m going to steal the base,” Cueto said in Spanish. “He always says, 'No.' I kept telling him that I was going to steal the base, so he finally gave me the green light, and I stole it.”