Enmanuel Valdez and Tyler O'Neill hit home runs as the Boston Red Sox defeated the host Seattle Mariners 5-1 Sunday afternoon, earning a split of their season-opening, four-game series.

Red Sox right-hander Garrett Whitlock (1-0) went five innings and allowed one run on three hits. He didn't walk a batter and struck out eight.

Boston relievers Greg Weissert, Joely Rodriguez and Justin Slaten combined to allow just one hit over four scoreless innings.

Seattle starter Bryce Miller (0-1) also pitched five innings but gave up four runs on six hits. The righty walked two and fanned six.

Both starters racked up three strikeouts in the first inning before allowing runs in the second.

With one out in the top of the second, O'Neill hit a first-pitch fastball at the top of the strike zone down the left-field line for his second homer of the season.

The Mariners responded in the bottom of the inning as Mitch Haniger led off with a double to center and advanced to third on Ty France's single to right. Whitlock struck out the next two batters before Josh Rojas grounded a run-scoring single to right to tie it 1-1.

The Red Sox regained the lead in the fourth. Triston Casas drew a leadoff walk and, an out later, O'Neill singled to right-center. Miller struck out Wilyer Abreu before Valdez hit a towering three-run shot down the right-field line on a 3-1 fastball.

Boston tacked on a run against reliever Cody Bolton in the sixth. Masataka Yoshida led off with an infield single off Bolton's glove, O'Neill walked and Abreu lined a single to right to load the bases with no outs. Valdez struck out before Reese McGuire hit a slow roller down the first-base line, with Bolton's only play to throw to first, to make it 5-1.

Third baseman Rafael Devers returned to the Red Sox's lineup after missing two games with left shoulder soreness. Mariners designated hitter Mitch Garver sat for the third straight day with back spasms.

--Field Level Media