Left-hander Wade LeBlanc watched as his teammates scored five runs before he even took the mound, then pitched seven shutout innings Thursday night, leading the Seattle Mariners to a 7-1 victory over the Oakland Athletics in the opener of a key American League West series in Oakland, Calif.

The Mariners (75-59) took advantage of a two-run throwing error and a bases-loaded walk in the first en route to snapping a three-game losing streak and moving within 4 1/2 games of the A's (80-55) in the duel for second place in the West and the second AL wild-card spot.

The clubs have six head-to-heads remaining, including three more this week in Oakland.

LeBlanc (8-3) easily made his early 5-0 advantage hold up, limiting the A's to three hits and three walks in his seven innings. He struck out four.

Mitch Haniger led off the first with a single against Oakland right-hander Frankie Montas (5-4), who had been called up from Triple-A earlier in the day to replace injured lefty Sean Manaea.

A one-out double by Robinson Cano and two-out walk to Kyle Seager loaded the bases, before Ryon Healy opened the game's scoring with an RBI single.

After Montas walked Ben Gamel to force in a second run, Oakland third baseman Matt Chapman threw wildly to second base on Mike Zunino's potential inning-ending grounder, allowing two more runs to score.

Dee Gordon followed with an infield single that made it 5-0.

Cano had an RBI double in the second inning and Haniger a solo home run, his 23rd, in the fourth to complete the Seattle scoring.

Montas pitched six innings, allowing seven runs (four earned) and eight hits. He walked two and struck out four.

Haniger, Cano, Healy and Gordon finished with two hits apiece for the Mariners, who hold an 8-5 lead over the A's in the season series.

Oakland totaled just four hits, including a double by Ramon Laureano.

The loss was the A's third in their last four games. They remained 2 1/2 games behind Houston (82-52) atop the AL West and 4 1/2 back of the New York Yankees (84-50) atop the AL wild-card race.

The Astros and Yankees also lost Thursday.

--Field Level Media