OAKLAND, Calif. -- What looked like a daunting road trip when they left home ended up being a winning one that the Tampa Bay Rays hope will provide a jolt of momentum for the stretch run.

Alex Cobb shut down Oakland for seven innings and Carlos Pena hit a home run to help Tampa Bay complete a successful nine-game trip by beating the Athletics 4-1 on Wednesday.

"Winning on the road is always more difficult," Pena said. "To come out of this road trip playing great ballclubs like the ones we did and win all three series is a great sign. It's a very positive sign. We want to ride this positive momentum."

Pena, who drove in five runs in the series, hit an RBI double in the sixth inning and a solo home run in the eighth for the Rays, who won three consecutive series on one trip for the fourth time in franchise history. The victories against Baltimore, the Angels and A's marked the first time Tampa Bay won three consecutive road series against winning teams.

"It's pretty spectacular," manager Joe Maddon said. "Before the trip everyone is talking 7-2. To me it's always about that night. To win each series is about as good as it gets right now."

Jeff Keppinger scored twice and Matt Joyce and Ryan Roberts also drove in runs for the Rays, who moved within 1½ games of Oakland for the second wild-card spot in the American League.

Brandon Inge hit a home run for the A's, who followed up the best July in club history by losing the first game of August. Oakland got back into the AL playoff race by going 19-5 last month, but the A's have dropped back-to-back games for the first time since losing three straight at Texas to end June.

"We're not going to be perfect and put seven or eight runs on the board every time," manager Bob Melvin said. "We're going through a rough patch. We'll be fine."

Cobb (5-8) followed up James Shields' shutout on Tuesday night with a strong start of his own, settling down after escaping a bases-loaded jam in the first. He allowed four hits and one walk, striking out six as the Rays lowered their ERA to 1.70 on the trip.

"It's just a contagious thing," Cobb said. "You see one pitcher doing good and you want to match him. You definitely don't want to be that guy to be the weak link in the rotation. As long as we can keep feeding off each other and throw strikes, we'll be fine."

After getting only one run of support while losing his previous three starts, Cobb took the mound with a 1-0 lead thanks to some rare small ball by the Rays. Desmond Jennings led off against Jarrod Parker (7-5) with a single, advanced to second on B.J. Upton's first sacrifice bunt of the season and scored on a two-out hit by Joyce.

Cobb struck out Brandon Moss with the bases loaded to end the bottom half, starting a run of 10 consecutive batters that he retired. That was snapped when Inge led off the fifth inning with his 12th home run to cut Tampa Bay's lead to 2-1, but Cobb pitched around a double by Kurt Suzuki to preserve the lead.

"He did a great job of getting strike one, a great job, all day long," Inge said. "He was 0-2 on a lot of guys and he made his pitches. He was effective."

Fernando Rodney pitched the ninth for his 31st save in 32 chances.

Keppinger doubled and scored on a two-out hit by Roberts to give Tampa Bay a 2-0 lead in the fourth. The Rays were unable to capitalize on another sacrifice bunt by Upton in the fifth when Ben Zobrist hit into a fielder's choice with runners on second and third and Joyce grounded out.

Pena's RBI double in the sixth made it 3-1.

Parker allowed three runs and eight hits in six innings. He gave up more than two runs for only the sixth time in 19 career starts.

Notes

• A's OF Josh Reddick went 0 for 4 to extend his career-worst hitless streak to 21 at-bats.
• The Rays optioned RHP Josh Lueke to Triple-A Durham after the game and will likely call up a position player when they return home Friday to face Baltimore.
• Oakland OF Coco Crisp (left hamstring) has made significant progress and could be back in the lineup soon, Melvin said.
• A's SS Cliff Pennington (left elbow) could begin a rehab assignment Friday.
• The Rays granted Hideki Matsui his release before the game. He was designated for assignment last week.
• The A's open a four-game home series against Toronto on Thursday when Bartolo Colon (7-8) takes the mound against Henderson Alvarez (7-7).