Ryan Kalish belted a grand slam and Jon Lester notched his 16th win as the Boston Red Sox defeated the Tampa Bay Rays 12-5 at Fenway Park Monday night.

The victory moved the Red Sox 6.5 games behind the Rays in the AL wild-card standings.

Lester (16-8) allowed four hits and two runs and struck out 10 in six innings. He retired the last 10 batters he faced.

Boston jumped on Rays starter Jeff Niemann (10-6) for six runs in two innings. David Ortiz hit a two-run homer, his 28th, in the first inning and Adrian Beltre followed with his 26th homer to give the Red Sox a 3-1 lead. Victor Martinez had a two-run single in the second and Ortiz followed with an RBI double to give Boston a 6-1 lead.

Kalish, who was one of six rookies to play for the Red Sox on Monday, highlighted a five-run fourth inning for Boston with his grand slam. First baseman Lars Anderson (0-for-4) and relief pitcher Robert Coello made their major league debuts.

The Rays took advantage of Coello’s wildness and scored three runs in the seventh inning to make it 11-5.