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Mike Kickham spent some time before his major league debut sitting at a clubhouse table alongside injured starter Ryan Vogelsong, the man he has replaced in the San Francisco Giants' rotation for the time being.

Kickham was eager to hear anything that might help prepare him for this level, and then he quickly received his introduction to the big leagues in a 6-3 loss to Jarrod Parker and the Oakland Athletics on Tuesday night.

"Obviously, I came into it expecting a little heightened emotions but I was able to do a better job than I thought I would (keeping them in check)," Kickham said. "After that first pitch it was like any other game. But mistakes here are magnified. I don't get away with what I do in Triple-A."

One of those was a two-run home run to Derek Norris in the second inning that gave Oakland the lead for good on the way to its fifth straight victory.

The Giants lost both games at the Coliseum in this interleague Bay Bridge Series between the two reigning West division winners. Now, it shifts to San Francisco for two starting Wednesday night.

Hunter Pence homered in the ninth and hit an RBI single in the first to give Kickham a lead before he took the mound for the first time. The 24-year-old Kickham (0-1) worked a clean first inning on nine pitches, hitting 92 mph on his first pitch. He reached 94 several times, too.

"He showed good stuff early. I'm sure he was amped up and then he got behind hitters but I liked what he showed," manager Bruce Bochy said. "It's his first outing and that's always one to put behind you."

Chad Gaudin, who was in the mix to make the start Tuesday night in place of Vogelsong, wound up pitching three innings. Bochy has said Gaudin is too valuable in relief to use him for a spot start.

Kickham might just be up for one more considering the Giants have three upcoming off days and don't need a fifth starter until mid-June. Vogelsong is recovering from a broken pitching hand.

Pence shared some encouraging words with Kickham before the game, too.

"Everyone's first time is exciting. We were excited to see him out there," Pence said. "He gained some pretty valuable experience. He competed. Sometimes the game can speed up. I thought his stuff was great, just missed some pitches."

Nate Freiman hit an RBI single and Jed Lowrie and Seth Smith each drew bases-loaded walks as Oakland (30-23) won for the 10th time in 11 games to move seven games above .500 for the first time since April 19.

Parker (3-6) quickly settled into a nice groove. He reached seven innings for the third straight start, earning his second victory over the last five starts after consecutive winless outings.

"His stuff's always been there. It's a matter of going out there and doing it," manager Bob Melvin said.

Norris connected in the second for his second home run. Yoenis Cespedes hit a one-out double in the third for the first 10-game hitting streak of his career. That sparked a mound visit by Giants pitching coach Dave Righetti with a runner also on third. Josh Donaldson was intentionally walked then Lowrie drew a bases-loaded walk to make it 3-1.

"You can talk about big hits, but you can also talk about big walks," Melvin said.

Freiman followed with an RBI single to chase Kickham. He was tagged for four runs on four hits in 2 1-3 innings with three strikeouts and four walks as the Giants lost for the seventh time in their last eight road games.

Marco Scutaro singled in the first as designated hitter against his former club. He scored on Pence's single. After that, Parker retired the next nine Giants batters in order before Brandon Belt's fourth-inning double.

Scutaro reached on a three-base error by A's right fielder Chris Young in the eighth but San Francisco failed to capitalize. Pence hit his eighth home run of the year off A's closer Grant Balfour.

The Giants missed center fielder and leadoff man Angel Pagan at the top of the lineup. He underwent an MRI on his injured left hamstring that revealed bursitis. He hasn't played since hurting himself in Saturday's game before his inside-the-park home run to win it 6-5 in the 10th inning against Colorado.

NOTES: Giants RHP Santiago Casilla underwent surgery to remove a cyst in his right leg. Bochy didn't have any details on the time table for his recovery. ... Bochy is considering giving his pitchers in a struggling rotation an extra day of rest with the off days. ... Oakland's pitchers were gearing up to bat at AT&T Park. ... Boston Marathon bombing survivor Aaron Hern, 12, threw out the ceremonial first pitch. He is from nearby Martinez. ... Norris hit his first career HR against the Giants last June 23. ... Kickham has been a roommate of manager Bochy's pitching son, Brett, throughout the minor leagues.