The Athletics jumped ahead early on Sunday, but couldn't hold onto a four-run lead in Anaheim and failed to complete the series sweep against the Angels, losing 6-5.
The A's bats were powerful during the three-game set in Southern California, as the second inning saw Oakland hit its eighth and ninth home runs of the series.
Sean Manaea exited the game with a 4-1 lead after five innings, but the Angels used a three-run seventh to jump ahead 5-4. Even after the A's capitalized on a Tony Watson error in the eighth to tie the game at five, Justin Upton's sacrifice fly put the Angels back in front for good in the bottom half of the inning.
Even as the decision was taken out of his hands, Manaea had nothing negative to say about the A's bullpen during his postgame press conference.
"Different outcomes, I think our relievers are great. Just happens to be one game, and yeah, just one of those games," Manaea told reporters Sunday.
The Houston Astros lost on a walk-off in Texas on Sunday, so the A's division lead remains at 1.5 games as the team gets set to return to Oakland to start a three-game series against the Seattle Mariners on Monday.
It won't be long before these two clubs see each other again, as the Angels will play a four-game series in Oakland beginning on Thursday.
The A's obviously would have preferred a sweep, but outscoring the Angels 19-12 over three games and seeing Matt Olson go yard in back-to-back games has to be a welcome sight for manager Bob Melvin and the rest of Oakland's coaching staff.
Frankie Montas will take the mound for the A's on Monday night against Yusei Kikuchi and the Mariners.