Soler hit a 1-0 curveball from left-hander Brian Johnson (1-1) just barely over the Green Monster to snap a 4-4 tie. The blast was Soler's third of the season.

Alex Gordon hit a tying homer in the ninth inning and Jon Jay went 4-for-5 with one RBI for the Royals.

Kansas City won for just the fifth time in its past 21 games.

Mitch Moreland and Eduardo Nunez homered for the Red Sox. Moreland and Andrew Benintendi each had three hits for Boston.

Gordon and Whit Merrifield recorded back-to-back singles off Johnson in the 13th prior to Soler's decisive blast.

The Red Sox pushed across two runs in the bottom of the 13th on an infield out by Jackie Bradley Jr. and Christian Vazquez's single before left-hander Brian

Flynn retired Nunez on a liner to center for his first career save.

Boston was two outs away from a victory when right-hander Craig Kimbrel served up the ninth-inning homer to Gordon. The blast was Gordon's first of the season and represented Kimbrel's first blown save in eight opportunities.

Kansas City moved ahead 4-3 in the 12th inning when Drew Butera doubled off right-hander Heath Hembree, moved to third on a bunt single by Ryan Goins and scored on Jay's sacrifice fly to left.

Royals right-hander Kelvin Herrera (1-0) was unable to hold the lead as he served up a tying one-out shot to Nunez in the bottom of the 12th.

Boston ace Chris Sale allowed two runs -- one earned -- and five hits over seven innings. The left-hander struck out six and walked two.

Kansas City right-hander Jakob Junis allowed two runs and seven hits over six innings. He struck out five and walked one.

Royals third baseman Mike Moustakas didn't start due to a bruised right forearm suffered Monday when he was plunked in the arm by Red Sox left-hander Eduardo Rodriguez. He was utilized as a pinch hitter in the 10th inning and grounded out.

Boston took a 3-2 lead in the seventh inning when Benintendi reached on a one-out double against left-hander Tim Hill and came around to score on two wild pitches from Royals right-hander Brad Keller.

Boston trailed 2-0 before Moreland drilled a one-out homer to right in the sixth inning. Bradley had a run-scoring single later in the frame to tie it.

--Field Level Media