Reed had a one-out RBI single off Kevin Jepsen (0-1) in the seventh to break the tie.
Roy Corcoran (6-2) went two innings to earn the victory.
J.J. Putz worked a routine ninth to pick up his 14th save of the season and the 100th of his career.
After Howie Kendrick bounced a two-out single through the middle in the second, Matthews crushed his two-run homer to deep center. It was his eighth of the season, but first since June 11 against Tampa Bay.
The Mariners tied it in the third when Johjima singled and advanced to third on a two-out double by Ichiro Suzuki that extended his hitting streak to 16 games. Yuniesky Betancourt drove in both with a broken-bat single to center.
Kendrick singled to begin the Angels' three-run fourth. Matthews walked and Napoli his a 447-foot shot off Ryan Feierabend.
Valdimir Guerrero made it 6-2 in the sixth with a sacrifice fly.
Angels LHP Joe Saunders remained in Los Angeles dealing with a reluctant kidney stone. It's not certain when he will rejoin the team but Scioscia indicated it won't be more than another day or two. ... RHP Dustin Moseley (2-4), recalled from Triple-A on Sept. 1, will fill Saunders' spot Thursday. ... Riggleman said RHP Carlos Silva, who came out of his previous start with back problems, is not going to start Thursday but there is still the chance he may start one of the weekend games.
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SEATTLE (AP) - The Los Angeles Angels, owners of the best record in baseball and the first team to clinch a playoff spot two weeks ago, still can't ease off the throttle with five games remaining.
The Angels have one final goal - home-field advantage throughout the playoffs - but the Seattle Mariners denied them that with a surprising 9-6 victory Tuesday night.
Kenji Johjima drove in three runs to lead the Mariners' comeback from a four-run deficit that snapped a 12-game losing streak.
