DENVER (AP) — Madison Bumgarner, the steadiest pitcher in the San Francisco Giants’ rotation so far this season, finally had an off night and it was a doozy.

Bumgarner botched a potential double play with an errant throw and gave up the first grand slam of his big league career in San Francisco’s 10-9 loss to the Colorado Rockies on Friday night.

The Giants had a season-high four errors in losing to the Rockies for the first time in 11 games.

“We shot ourselves in the foot,” Giants manager Bruce Bochy said. “That’s what stands out. There’s too many errors, particularly in this ballpark. Walks and errors kill you. Madison hurt himself there. He handles that, it’s a double play. ...

“We let them get back in the game because of our mistakes there. They fought back, I’ll say that. But we’re making way too many errors. We’ve got to tighten things up.”

Bumgarner (4-2) gave up a career-high nine runs in 4 2/3 innings, including a tie-breaking grand slam to Jordan Pacheco in the fifth inning, the last hitter he faced. It was Pacheco’s first homer of the season and first slam of his career.

“I don’t know if there was one thing really,” Bumgarner said. “That grand slam wasn’t too fun. I just wasn’t making pitches when I needed to get guys out.”

Bumgarner lost on the road for the first time this season while turning in his first clunker against the Rockies in quite a while. He had gone 6-0 with a 2.08 ERA over his previous seven starts against the Rockies.

By the time his night was done, his ERA climbed nearly a full run to 3.09.

“It wasn’t one of the days where you really had great stuff,” said Bumgarner, who couldn’t hold an early 4-0 lead. “But I don’t think I did a good job of pitching with what I had.”

Jorge De La Rosa (5-3) entered the game without giving up a run at Coors Field in 12 innings. He was hit hard, surrendering five runs in five innings, only to settle down enough to earn the win.

The Giants, who rallied from an early six-run deficit the night before, were on the comeback trail again Friday.

Down five, they made things interesting by scoring three times in the seventh. It could’ve been more, but Dexter Fowler made a diving catch in center to end the inning.

“He made a great play on that,” Bochy said. “That’s what speed does for you in the outfield.”

Buster Posey made it a 10-9 game in the eighth with a two-out homer off Matt Belisle. Hunter Pence followed with a double, only to be stranded when Brett Pill grounded out.

In the ninth, Rafael Betancourt struck out the side for his 10th save in as many chances.

Carlos Gonzalez, Troy Tulowitzki and Wilin Rosario — the heart of the Rockies’ batting order — finished with a combined six hits, four RBIs and five runs scored. Gonzalez added an insurance run with a solo homer in the sixth.

Pablo Sandoval had three hits and drove in two runs for San Francisco, while Marco Scutaro extended his hitting streak to 16 games.

Trying to preserve a one-run lead in the fifth, Bumgarner gave up a game-tying single to Rosario. A walk to D.J. LeMahieu loaded the bases for Pacheco, who sent the first pitch from Bumgarner over the fence.

The Giants had a frightful night in the field, including missing a possible double play on Nolan Arenado’s comebacker when Bumgarner hurried his throw on the attempted force at second and it sailed over Brandon Crawford’s head into center field, allowing an unearned run.

“I just felt like I needed to rush it, which I didn’t,” Bumgarner said. “Take a couple of steps and let him get to the bag. I probably would still have had time to turn it. But even if he didn’t, it would have been better to get one out than have guys on second and third with no outs.”

Two more miscues came in the third, when Sandoval had a throwing error to begin the inning and center fielder Angel Pagan later sent a high throw to third base that ended up in the Giants’ dugout, allowing Dexter Fowler to trot home. Tulowitzki tied the game at 4 with an RBI single.

Scutaro gave the Giants a 1-0 lead when he jogged home on Posey’s sacrifice fly in the opening frame. The hot-hitting Scutaro is batting .485 during his streak.

NOTES: Giants RHP Tim Lincecum (3-2) will start Saturday night. ... San Francisco is 31-10 against Colorado since 2011. ... The Rockies altered their starting rotation, with RHP Tyler Chatwood getting the start on Saturday and RHP Juan Nicasio being bumped back to Sunday. Chatwood joined the team from Triple-A Colorado Springs on Friday and will be added to the roster before his start.