Boston, MA (Sports Network) - Daniel Nava drove in a pair of runs during a four-run sixth inning and Darnell McDonald hit an insurance RBI single in the eighth as Boston slogged through a 5-3 decision over Seattle in the opener of a day-night doubleheader at rain-soaked Fenway Park.
Adrian Beltre and Mike Lowell also knocked in a run each for the Red Sox, who have won four in a row.
Josh Beckett (4-3) allowed four hits and three runs in 6 1/3 innings, fanning seven with one walk. Jonathan Papelbon turned in a scoreless ninth for his 32nd save.
Casey Kotchman hit a two-run homer and Russell Branyan added a solo blast for the Mariners, who have dropped four straight.
David Pauley (2-5) yielded six hits and four runs over 5 2/3 frames in defeat.
The second game is set for 7:10 p.m. (et) with Boston's Jon Lester opposing Seattle's Felix Hernandez.
Down by four, Seattle struck back in the seventh as Branyan hit a one-out solo shot then after a Jose Lopez single, Kotchman reached the bullpen in right for a 4-3 game and Beckett's outing was over.
Daniel Bard came in and prevented further damage by retiring the next two batters on groundouts, then left two runners on in a scoreless eighth.
In the home half, Beltre and Lowell worked two-out walks against Jamey Wright, then McDonald sliced a ball to left that scored Beltre for a 5-3 game. The rally ended when Lowell was thrown out trying to advance to third.
Papelbon backed up the offense by setting down the Mariners in order in the ninth.
The Sox broke a scoreless tie in the sixth. After loading the bases on a pair of singles and a walk, Beltre's comebacker to the mound plated one run. Lowell followed with a sac fly to right, then Nava dumped a two-run single to right for a 4-0 lead.
Boston has won four of six over Seattle this season...Branyan's blast was his 20th of the season, marking the third time in his career and second straight season he's reached the feat...Beckett picked up his first win since August 3, going 0-2 with a no-decision since then...Pauley had won his previous two starts.