Updated

Adam Rosales scorched a leadoff homer in the bottom of the eighth inning to lift the Oakland Athletics to a 2-1 victory over the Kansas City Royals in the opener of a three-game set at the Coliseum.

Kansas City starter James Shields stifled the A's for much of the night, but served up a leadoff blast to Josh Donaldson in the seventh that tied the game.

After Sean Doolittle (3-0) blanked the Royals in the top of the eighth, Rosales ripped Shields' third offering of the home half over the left-field wall for the go-ahead run.

Grant Balfour spun a perfect ninth to nail down his seventh save of the season for the A's, who had dropped two straight.

Shields (2-4) went the distance in defeat, striking out nine and giving up just six hits and a walk over eight efficient frames.

"Today is just a case of me not doing my job," Shields said. "That's it. Bottom line. I don't care what the score of the game is. I didn't get the job done there at the end. It's a tough loss. A real tough loss."

David Lough, who was recalled from Triple-A Omaha before the game, collected two of Kansas City's five hits and knocked in the lone run for the Royals, who have lost five of their last seven games.

Lough gave the visitors an early advantage in the third when he dropped a two- out double into center field to score Salvador Perez, who smacked a two-bagger of his own earlier in the frame.

Lough's run-scoring double was the lone blemish of Jarrod Parker's outing, as the Oakland starter allowed just four hits and two walks while striking out five over seven solid frames.

"It seemed like there was a calm to him today," A's manager Bob Melvin said of Parker. "It seemed like he was more confident. We've seen him pitch that type of game quite a few times. He was really good today."

Parker did not factor in the decision however, as the A's were unable to break through against Shields until the eighth.

Game Notes

Lough was recalled after the team placed outfielder Jarrod Dyson on the 15-day disabled list with a right ankle sprain ... Shields has posted a quality start in each of his four losses, with the Royals losing each one by just one run ... Oakland went 0-for-2 with runners in scoring position and left four on base.