ST. PETERSBURG, Fla. -- The Oakland Athletics had lost four straight games and eight of nine, but they found success from unlikely sources in a 5-0 win over the Tampa Bay Rays at Tropicana Field on Saturday.

Rookie starter Kendall Graveman, who came in with an 8.27 ERA, pitched six innings of scoreless, three-hit baseball. And four of Oakland's runs came with two outs in the sixth, with clutch hits from the bottom of the lineup and two Rays errors on one play.

"We had a couple of matchups we don't normally do, but they came through for us today," A's manager Bob Melvin said. "They give you a win is what they did, and we desperately needed a win there."

Oakland (15-30) bounced back nicely and Tampa Bay (24-20) remained 1 1/2 games up in the American League East despite managing just six hits and being shut out for the fifth time this season.

Tampa Bay starter Nathan Karns left with a shutout and two runners on, but reliever Xavier Cedeno couldn't get the final out to escape the jam.

Cedeno gave up an RBI single to second baseman Eric Sogard, who was hitting .154 with no RBIs in 26 at-bats against lefties this season. Cedeno then walked first baseman Mark Canha, the team's No. 8 hitter, to load the bases.

Left fielder Sam Fuld -- who rarely stays in the game against lefties and was 0-for-4 all season -- hit a single to center field to score one run, and center fielder Kevin Kiermaier misplayed the ball, allowing a third run to score.

Kiermaier's perfect throw home was dropped by catcher Rene Rivera for a second error, allowing the fourth run -- the third on the play -- to score.

"We played good baseball every inning but one today," Rays manager Kevin Cash said. "We were a pitch away from (a) 0-0 ballgame going into the bottom of the sixth. It just didn't happen."

Called up to help an overworked bullpen, Rays reliever Enny Romero made his season debut but struggled, walking four consecutive batters in the eighth to give the A's a 5-0 lead.

The Rays got two singles and a walk off reliever Tyler Clippard in the ninth, but pinch hitter Joey Butler struck out to end the game.

The win marked Oakland's sixth shutout of the season, but its first since April 18 -- the A's had five in their first 12 games but none in the next 32 until Saturday.

"We didn't really have a time period when he was threatened, other than that one inning," Rays infielder Nick Franklin said. "He felt really comfortable and we didn't get him off his game."

Graveman was called up for a second shot as an injury replacement after having an 8.27 ERA in four starts in April. He had a 1.85 ERA in four minor-league starts and held the Rays to three hits and no runs in the six innings. He struck out six and walked two while throwing 93 pitches.

"I felt comfortable out there -- the defense played great behind me," Graveman said. "There wasn't much I could have asked for."

While not nearly as dominating, Rays starter Nathan Karns matched him on the scoreboard, holding the A's scoreless despite giving up six hits in the first five innings.

Oakland had its chances, stranding two in the second and the fourth, but Karns got out of trouble both times.

The Rays got a leadoff double from third baseman Logan Forsythe in the fifth, then left fielder David DeJesus was hit by a pitch. Despite having two on and none out, the Rays couldn't convert the opportunity; catcher Rene Rivera, hitting .148 entering the game, made the final out of the inning.

NOTES: With a bullpen in need of rest, the Rays made a move to add a 13th arm to the active roster, sending INF Tim Beckham to Triple-A Durham after he hit a home run and triple Friday and called up LHP Enny Romero, who can provide long relief. Romero has pitched in only one major-league game, with the Rays in 2013. ... Despite winning, the Athletics are an MLB-worst 2-13 in day games, compared to 13-17 in night games. They have hit 30 of their 39 home runs at night. ... Oakland has the majors' worst record in one-run games (2-13) and is 0-6 in extra innings.