McCarthy was lifted after giving up hits to Brandon Belt and Ryan Rohlinger to open the eighth.
Aubrey Huff hit a three-run homer off Fernando Cabrera, who relieved McCarthy.
McCarthy gave up five hits and had good control. He struck out five without walking a batter. It was the longest outing of the spring for an Oakland pitcher, surpassing Trevor Cahill's 6 1-3 innings Saturday.
Chris Carter hit a two-run triple in the eighth for Oakland.