Semien went 1-for-3 with a solo home run in a shutout win over the Angels on Thursday.
Semien's 394-foot shot to center off Trevor Cahill extended the Athletics' lead to 3-0, and the shortstop's season-opening hitting streak to three games. The 28-year-old ceded the leadoff spot to Robbie Grossman on Thursday, but manager Bob Melvin is likely to rotate Semien into the top of the order fairly frequently over the course of the season.