Mike Lowell hit a two-run single off Sean Green in the 12th inning, and the Red Sox took advantage of two outfield errors to beat the lowly Mariners 6-3 on Wednesday and complete Boston’s first series sweep at Seattle in 15 years.

The Red Sox entered the series having lost eight of 11 on the road, leaving manager Terry Francona to say he was perplexed. They flew home for a weekend against the surging New York Yankees after their first three-game sweep on the road this season.

Boston stayed a half-game behind first-place Tampa Bay in the AL East.

Raul Ibanez and Jose Vidro hit home runs for Seattle, which lost its fifth consecutive game. The Mariners expected to be in the postseason but sunk to a season-low 25 games under .500 and are in clearance-sale mode for the July 31 non-waiver trading deadline. Ibanez and Vidro are top candidates to go.