CINCINNATI (AP) — The Reds lost a series and got another concern about their pitching staff.

Left-hander Madison Bumgarner got his career-high sixth straight win, and the San Francisco Giants beat the Reds 6-1 on Thursday afternoon, taking a series in Cincinnati for the first time in five years.

The Reds won the series opener, pushing their winning streak to a season-high four straight. Then they dropped the last two, scoring a total of three runs.

Michael Morse hit a two-run homer, and Brandon Crawford broke out of a slump with a three-run shot off Mike Leake (3-5), who had overwhelmed the Giants the last four times he faced them. He wasn’t fully healthy this time around.

Manager Bryan Price revealed after the game that Leake has been limited by a stiff neck in his last three starts, interfering with his delivery.

“He’s been battling some stiffness in his neck that makes it hard for him to get his head fully turned toward the catcher’s glove,” Price said. “We’ve been trying to get him over the hump with that, but it still keeps acting up.”

The Giants won the series by finally getting to Leake, who was 4-0 in his last four starts against the Giants while allowing only three earned runs. Leake lasted only five innings and gave up eight hits, a walk and five runs.

Leake said the stiff neck sometimes prevents him from fully extending his arm as he throws the ball.

“Even today, I had a slight tightness and I couldn’t get it out of there,” Leake said. “It doesn’t affect me on one pitch more than another. I just wasn’t throwing the ball where I wanted to today.”

Morse homered for the second straight game, connecting for his team-high 13th homer in the second inning. That ended Leake’s streak of six straights without giving up a homer.

Crawford’s seventh homer in the fourth inning was his first since May 21. The shortstop was in a 4 for 32 slump.

Pablo Sandoval singled three times and scored a pair of runs, improving to 11 for 17 career against Leake with two homers. Hunter Pence extended his hitting streak to six games.

San Francisco moved a season-high 18 games over .500 with its 11th win in 14 games. The Giants have the best record in the majors at 39-21.

Bumgarner (8-3) gave up three hits in eight innings, including Todd Frazier’s homer, and retired the last 16 batters he faced. He’s 6-0 in his last seven starts, the best such streak of his career.

Bumgarner was the NL’s Pitcher of the Month in May and carried it into June with another stingy performance on the road. Bumgarner has allowed three or fewer runs in each of his last 20 road starts, a franchise record.

George Kontos retired the side in the ninth as the final 19 Reds went in order. Cincinnati didn’t have a base runner after Frazier singled with two outs in the third inning.

Frazier hit his team-high 12th homer in the first inning, his second homer in two games. He’s got a six-game hitting streak that includes three homers.

The Giants hadn’t won a regular-season series in Cincinnati since Aug. 18-20, 2009. They’ve dropped 11 of their last 14 at Great American Ball Park during the regular season. San Francisco’s best moment there was a division series win in 2012 that started the Giants toward a World Series championship.

NOTES: The Giants open a 10-game homestand against the Mets, Nationals and Rockies on Friday. Matt Cain (1-3) will be activated off the DL to face Jonathon Niese (3-3). … The Reds continue their 10-game homestand against the Phillies, with Johnny Cueto (5-4) going against LHP Cole Hamels (1-3). … Price won a challenge in the third. Umpire Larry Vanover decided that Brayan Pena pulled his foot off first base while reaching for a throw, leaving Buster Posey safe. The call was overturned on review. … The Reds are undecided on whether RHP Mat Latos, who left a rehab start on Wednesday night after 67 pitches because of a calf cramp, will need to make one more start in the minors before he’s activated.

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