OAKLAND, Calif. -- The Oakland Athletics have been waiting for the day when their offense, defense and pitching all came together.
It's been rare so far. There have been late-inning collapses by a tired, overworked bullpen and demoralizing one-run defeats when the offense couldn't get it done.
Jason Giambi homered a day after reaching the 400 milestone and Landon Powell hit a tiebreaking shot for his first career home run as the A's avoided a sweep with a 6-2 victory over the Arizona Diamondbacks on Sunday.
"It's good to get one of these in our favor," Powell said. "I hope it gives us momentum."
Giambi, who on Saturday night became the 44th player in major league history with 400 homers, provided an insurance run with his seventh-inning solo drive.
Rookie Josh Outman (2-0) worked out of jams all day and hung tough with Jon Garland (4-3), who pitched five scoreless innings before running into trouble.
The A's lost 8-7 in 11 innings Saturday and had played four straight one-run games. Their win Sunday ended a three-game skid overall and six-game home losing streak to Arizona.
The Diamondbacks had won a season-high four in a row.
Powell, the backup catcher who has been nursing a strained right hamstring, connected in the sixth and gingerly rounded the bases. He homered moments after the A's tied it at 1 on Garland's wild pitch, and has 11 RBI in 12 big league games.
Outman described Powell's trot as "pretty bad."
Powell, who got the home run ball back as a souvenir, hadn't made that kind of contact since injuring his leg last Monday -- and he felt a surge of pain.
"I was trying my best not to limp because I knew the guys would be giving me some Kirk Gibson references," said Powell, whose homer was witnessed by Gibson himself in the other dugout as D-backs' bench coach. "I kind of froze, like 'ow.' I wasn't trying to pose or show up their pitcher. I was just trying not to fall down."
It was in Game 1 of the 1988 World Series when Gibson stepped in with two outs in the bottom of the ninth and connected for a pinch-hit, walkoff homer against Oakland's Dennis Eckersley for a 5-4 Dodgers win. Gibson, who didn't start because of a strained left knee, limped around the bases in one of the most dramatic games in Series history.
Outman won his outing with an unusual pitching line: five walks but no strikeouts, and only four hits in 7 2/3 innings.
Oakland's defense was key. The A's turned four double plays -- in the fourth, sixth, seventh and eighth innings. Outman has allowed only two earned runs over his last 19 2/3 innings.
Adam Kennedy added a two-run single in the eighth for Oakland.
Stephen Drew had an RBI groundout in the first and Arizona added another run when Chris Young scored on a double-play grounder in the eighth.
The Diamondbacks concluded a 6-3 road trip under new manager A.J. Hinch, the former A's draft pick out of Stanford.
"It was a great road trip," Hinch said. "We're in a better place today as a team than we were when we left. This road trip was a success on many levels."
The 38-year-old Giambi hit his 192nd home run for Oakland, tying Sal Bando for fifth place in Oakland history and eighth place in franchise history. Giambi returned to the A's -- the team that drafted him in 1992 -- this season for a second stint following seven seasons with the Yankees.
Garland lost his third straight to the A's dating to last season while with the Angels. He is 4-12 lifetime with a 5.66 ERA against Oakland.
"I was kind of all over the place there for a while with some walks, but when the time came I was able to make a pitch to help me out," Garland said.
Every A's starter but Travis Buck had a hit. ... The D-Backs don't envision leadoff man Felipe Lopez needing a DL stint after he injured his left hamstring on the bases Saturday night. Hinch held Lopez out Sunday and might do so again for Monday's home game against San Diego. ... Having made two starts at 1B since coming off the disabled list Friday following a calf injury, Oakland's Nomar Garciaparra got the day off to rest and recover. ... First-pitch temperature for all three games was 50 degrees.