OAKLAND, Calif. — Jake Lamb hit a two-run homer once Oakland finally got to San Francisco’s bullpen, and the playoff-bound Athletics beat the Giants 6-0. Jesús Luzardo pitched six innings to end a four-start winless stretch. The A’s clinched their third straight postseason berth Friday and were closing in on the club’s first AL West crown since 2013. Oakland can win the division title with a win Sunday.