Colon (3-0) dominated the Red Sox, issuing just one walk while striking out seven over seven innings before the game was cut short due to rain.
Seth Smith led the A's at plate, cracking a two-run homer en route to three RBI.
Red Sox starter Alfredo Aceves (1-1) lasted just 3 1/3 innings after being roughed up for eight runs (seven earned) on seven hits and four walks.
Boston's loss was its third in four contests.
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