Vladimir Guerrero Jr. capped a two-run ninth inning with a walk-off single as the Toronto Blue Jays defeated the visiting Boston Red Sox 6-5 on Tuesday.
Pinch hitter Alejandro Kirk singled to lead off the bottom of the ninth against Tyler Danish (2-1), and George Springer walked.
Hansel Robles replaced Danish and allowed Bo Bichette's single that scored pinch runner Bradley Zimmer to tie the game to set up Guerrero's winning hit.
Christian Vazquez singled home a run in the eighth inning to give Boston a 5-4 lead.
Rob Refsnyder hit a two-run home run and Trevor Story added a solo shot for the Red Sox, who have lost the first two games of the three-game series.
Toronto right-hander Ross Stripling allowed two runs, five hits and one walk while striking out three in five innings.
Boston right-hander Michael Wacha gave up four runs, seven hits and three walks in five innings. He fanned two.
Bichette and Guerrero took one-out walks in the first inning, and Teoscar Hernandez doubled off the left field wall just beyond the reach of Alex Verdugo, putting Toronto up 1-0. Matt Chapman's two-out double drove in two more runs.
Story hit his 12th homer of the season, with two outs in the second, cut Boston's deficit to 3-1.
Lourdes Gurriel Jr. doubled with one out in the third and scored on Santiago Espinal's two-out single.
Vazquez led off the fifth with a single, took third on Franchy Cordero's double and scored on Refsnyder's groundout.
Verdugo extended his hitting streak to nine games with a two-out single against Adam Cimber in the sixth.
Toronto's Trent Thornton walked Cordero with one out in the seventh. After Christian Arroyo's grounder forced Cordero at second, Refsnyder hit his second homer of the season, a blast to center that tied the game at 4.
Xander Bogaerts walked and Verdugo singled to open the Boston eighth against Tim Mayza. Vazquez hit a one-out, RBI single.
Jordan Romano (2-2) pitched around a walk in the top of the ninth.
--Field Level Media