ANAHEIM -- The A's newest bullpen arm was on display Friday evening. But another was in rare form.
Usually unhittable, Lou Trivino was tagged for a two-run, go-ahead homer off the bat of Justin Upton in the sixth, setting up a rather anticlimactic inning for the just-acquired Fernando Rodney.
Rodney offered a clean seventh, but the A's late-inning magic betrayed them in this one, leading to a 4-3 series-opening loss to the Angels that loosened their hold on the second American League Wild Card spot.
• Rodney hinting at new celebration with A's
With the Mariners topping Houston on Friday, the A's lead shrunk to 1 1/2 games -- three days before the pair of Wild Card contenders are set to square off in Oakland.

"It's frustrating knowing it's your fault you lost the game, but I have confidence that I'm still good enough," the rookie Trivino said. "It just stinks. I'll be fine tomorrow and move on from here."
The A's got homers from Matt Chapman (16) and Khris Davis (33) in the first inning for a swift three-run advantage against Angels starter Felix Pena but managed little thereafter, mustering just three hits in their final eight innings.
Lefty Brett Anderson was pulled at 63 pitches following five innings of two-run ball -- his lone blemish a two-run homer to Kole Calhoun in the third -- as the A's continue to lean heavily on their typically trusty bullpen. But Trivino yielded three consecutive hits before recording an out, the middle one landing in the visitor's bullpen.
"I was just trying to get it down and away, and I struggled to stay behind the ball today and paid the price for it," Trivino said. "When you're not behind the ball, you don't have the action you want it to have. Everything was flat, so they were able to see it."

Trivino entered the day with the seventh-lowest WHIP in the AL (0.98) and had allowed just three runs combined over his previous 27 games, prompting expectations of near-perfection each time he toed the rubber.
Collectively, the A's bullpen has provided just that of late, which is why the Athletics have opted to pull their starters earlier and earlier.
"Brett came out after five with the lead, and we had the middle of the order, righties, coming up, and that's usually a pretty good time for Lou," A's manager Bob Melvin said. "They just hit him tonight, and that doesn't happen very often. You're going to give up some runs from time to time. He's been absolutely fantastic for us this year. It really came down to us not swinging the bat really after the first inning."
For Anderson, though, it will take some time for this 10-year veteran to acclimate to such a setup.
"We live and die by our bullpen, and those arms are tremendous down there," Anderson said. "More times than not, we're going to come out with a victory, but being a starter for as long as I have, the goal is to go as deep and be as efficient as you can, but it's kind of the way our team works, so we're going to have to get used to it."
SOUND SMART
Chapman, who finished 2-for-4, has reached base safely in 24 consecutive games, which is the second longest active streak in the Majors (Matt Carpenter, 28). Chapman is batting .338 in that span.
YOU GOTTA SEE THIS
With one out in the first, Chapman lifted a solo shot to center field against Pena for his 16th of the season, in front of his hometown crowd no less. Jed Lowrie responded with a base hit, and Davis drilled his team-leading 33rd homer to center for a swift three-run advantage.

Davis, who also increased his RBI total to 90, second-most in the Majors, has 12 home runs in 19 games since the All-Star break -- and 118 since the start of 2016, tops among all players.
HE SAID IT
""There's no arguing with Lou Trivino's stuff. It's better than mine. But it's always tough, because it's ingrained into your psyche as a starter, to go as far as you can, as long as you can." --Anderson, on being removed after allowing two runs in five innings. 
UP NEXT
The A's will send right-hander Edwin Jackson (3-2, 2.87 ERA) to the mound for Saturday's 6:07 p.m. PT matchup at Angel Stadium. On the other side, lefty Tyler Skaggs is expected to come off the disabled list (adductor strain) to make his first start since July 31. He is 8-7 with a 3.34 ERA.