PHOENIX (AP) -- Justin Upton has been putting in extra time in the batting cage to try to break out of his slump.
All he needed was a day off.
After being benched for one game, Upton hit an eighth-inning tiebreaking homer to lead the Diamondbacks to a 2-1 victory over the Oakland Athletics on Thursday. He also doubled and scored Arizona's other run.
"It has been pretty tough, but in the end, it's a game where you're going to fail a lot, and it's something you have to live with," said Upton, who had been 0-for-10 with seven strikeouts during a six-game homestand. "But to play the way I did today, hopefully it turns things around."
Upton might have been a little surprised when he arrived at Chase Field on Thursday morning and saw his name in the No. 2 hole in the lineup. But manager Bob Melvin said he never lost faith in Upton, and Upton made him look smart.
In the fourth, Upton doubled and scored on Chris Young's sacrifice fly.
With the game tied 1-all in the eighth, Upton drove a 3-2 slider from Keith Foulke (0-2) into the pool area in right-center field for his ninth homer and first since May 31.
Not bad for a 20-year-old in his first full major league season.
"For a kid to have that kind of presence of mind, to go up there each and every at-bat, going through some struggles like that ... at 20 years old that just doesn't happen," Melvin said.
Upton helped the NL West leaders salvage the final two games to finish a 3-3 homestand against Kansas City and Oakland. The Diamondbacks, who are 15-19 on the road, left after the game for a nine-game trip to Minnesota, Boston and Florida.
"It makes the plane trip a lot better, that's for sure," Arizona starter Doug Davis said.
Upton, who turns 21 in August, got off to a strong start this season. He was hitting .333 on May 2, but his average steadily declined, and he entered Thursday's game at .244. What's worse, he had 84 strikeouts in 225 at-bats.
As Upton struggled, there was talk that the club was considering sending him to the minors when left fielder Eric Byrnes comes off the disabled list, which is projected for Monday.
That seems a remote possibility if Upton can keep swinging the way he did on Thursday.
"There's no confidence issues," Upton said. "It's just baseball. A lot of people who don't play the game don't know how tough it is mentally and how physically draining it is on the body. You can so quickly lose your swing and your mental approach at the plate, and you've just got to find it again."
After scoring 15 runs in the series opener, the Athletics quickly lost their way at the plate. They mustered a total of two in the final two games, both losses.
Oakland struggled against Davis, making his sixth start since returning from cancer surgery. Davis retired 11 in a row from the second to the fifth, striking out four straight at one point.
"Davis was mixing it up, throwing a lot of off-speed, a lot of slow breaking balls," Oakland manager Bob Geren said. "Kind of upset the hitters' timing a little bit. He pitched well."
Leading 1-0, Davis ran into trouble in the sixth. He walked Mark Ellis and gave up a single to Ryan Sweeney. Jack Cust followed with a bloop single down the left-field line that dropped in front of a sliding Chris Burke, scoring Ellis to tie the game at 1. Bobby Crosby then grounded into an inning-ending double play.
Davis went six innings, allowing one run and three hits. He walked two and struck out eight, a season high.
After giving up five runs in 3 2/3 innings on June 8, Davis has allowed one run in his last 13 innings.
Smith, a former Arizona farmhand, gave up one run and three hits in five innings, walking three and striking out four.
Smith said he was pleased to give up only one run in the fourth after Arizona loaded the bases with one out.
"I felt like I controlled the damage a little bit, getting out of there with only one run," he said.
Oakland RHP Brad Ziegler picked Mark Reynolds off first base in the sixth. ... Oakland CF Ryan Sweeney singled in the sixth to extend his hitting streak to 13 games, the longest for the A's this season. ... Arizona took two of three this week but Oakland still leads the all-time series 10-8. ... Athletics RHP Rich Harden (4-0, 2.53 ERA) starts the opener of a three-game series against Florida on Friday night in Oakland. Harden has allowed three runs or fewer in six straight starts. ... Arizona has led the NL West for 67 straight games, one shy of the team record set from July 16 to Sept. 29, 2002.