Wilson pitched 6 1/3 innings of two-run ball in a 123-pitch outing, Trumbo homered in his third straight game, Mike Trout added a triple and a solo shot and Frieri -- pressed into action when Scott Downs exited the eighth with pain in his right rib cage -- kept a one-run lead intact by recording the last five outs.
But if not for the aggression of Cespedes, mixed with the hard turf of the O.co Coliseum, the Angels are probably feeling a lot different heading home.
Cespedes was hit by a pitch to lead off the ninth, then initially got to second safely on a steal attempt off Hank Conger. But the A's center fielder slid well past the bag, and Howie Kendrick kept the tag on him before he could retreat.
"He's aggressive and goes in with a lot of velocity," said A's manager Bob Melvin, whose club snapped a three-game winning streak to move to 16-13. "He had the bag stolen, obviously. He just slid past it."
And because he did, the Angels recorded a critical first out in a frame that saw Frieri walk two additional batters.
"That was a big one, to be honest with you," said Kendrick, who had two singles and a solo homer. "That changes the situation with a guy in scoring position right there, because the smallest thing can turn into a tie game."
Two days earlier, Frieri blew his chance at a four-out save by giving up a game-tying hit to Cespedes in the ninth -- 10 innings before the A's won the longest game in both clubs' histories. On Wednesday morning -- knowing the Angels' bullpen has four relievers on the disabled list and has hardly caught a break all year -- Frieri walked into Mike Scioscia's office with a clear message.
I've got two innings if you need it.
"We said, 'No, that's ridiculous,'" Scioscia recalled, "so we had him go 1 2/3 innings."
Frieri pretty much had to. Wilson left a short-handed bullpen with eight outs left, and Downs cut the Angels' lead from three to one by giving up a double to Luke Montz and a single to Adam Rosales.
When Frieri checked into the ninth, he had already thrown 15 pitches -- but nobody was going to warm up in the bullpen.
"I'm always down for whatever Scioscia needs," Frieri said shortly after getting pinch-hitter Eric Sogard to fly out in foul territory and end the game. "No matter what the situation, no matter what team, no matter what hitter, I'm going to be able to go out there and do my thing."
Wilson pitched into the seventh for the first time all year and brought his ERA down to 4.04 in a typical outing that saw him walk five batters, hit another and scatter six hits. The fact he even got that far, with 73 pitches under his belt after the third inning, was a feat in and of itself.
"I knew the way things were going with the bullpen I was going to have to throw a lot of pitches one way or the other," Wilson said. "It was frustrating because I feel like I made some really good pitches. Give credit where it's due. Those guys, if they got to two strikes, they fouled a lot of pitches. They took some close pitches they didn't really chase. That's a good baseball team. I'm just trying to stay on top of my game and not give in when the situation is tough."
Everything is tough for the Angels these days, even when they win. When they arrive in Southern California on Wednesday night -- for a four-game homestand against the Orioles, just before departing for another two-city trip -- they'll still have a litany of players on the disabled list and have no idea who will get outs in the bullpen on a given day.
But problems like those are always easier to deal with after victories.
"Every win is going to be big for us," Trout said. "We have good teams like the Oakland A's. They're grinding, they're playing 100 percent every pitch. You can't take anything away from them. When they're down, they just keep fighting and fighting and fighting. That's what we need to start doing."