Giants right-hander Kevin Gausman (3-3) matched Luzardo nearly pitch-for-pitch, also completing three innings without allowing a hit.
But the A’s made the most of their first hit in the fourth, getting on the board first when Mark Canha walked, took second on a wild pitch and scored on an Olson two-out single.
Gausman was pulled after six innings, still having allowed just the one run and one hit. He walked three and struck out six.
Lamb’s homer, his second in five games since joining the A’s from Arizona, came off Sam Selman after a one-out single by Ramon Laureano to trigger the five-run seventh.
Tommy La Stella, another in-season acquisition by the A’s, added a two-run triple and Semien an RBI double before inning’s end, opening a 6-0 advantage.
Solano was the only player in the game with multiple hits, finishing with a pair of singles for the Giants.
Each team totaled six hits.
–Field Level Media