Huge blast by Luis Barrera wins it for Oakland Down to their last strike and nobody on base, the A’s rallied to walk-off in Game 1 of Saturday’s doubleheader, beating the Los Angeles Angels 4-3. The starting pitching was fantastic, yielding just a first-inning run, and the defense made a few nice plays in the field. The bullpen wasn’t perfect on a day it looked like they needed to be because, as has been the case too many times this season, the offense just disappeared for most of the game. But a massive three-run home run by an A’s prospect…