Vlad Jr.'s 424-foot moonshot came in the bottom of the fifth inning during the 6-5 loss to the World Series champions on Wednesday. Guerrero was 2-for-6 with an RBI, a run scored and a strikeout in the extra-innings loss.
The Red Sox jumped ahead 2-0 with RBI singles from Mitch Moreland and Xander Bogaerts in the third inning. Boston went down in order in the top of the fourth frame, before Guerrero walked to the plate to leadoff the bottom of the inning for Toronto.
The rookie slugger worked a 2-1 count against Boston starter Rick Porcello, before eyeing his fourth offering. Porcello tossed in a 90.8 mph fastball for the final pitch of the exchange. Guerrero turned on the pitch and blasted it over the center field fence for his fifth home run of the season.
Guerrero's long ball had an exit velocity of 109 mph and a launch angle of 23 degrees, according to Statcast.
Mitch Moreland plated Jackie Bradley Jr. on an RBI ground out in the seventh inning to give Boston a 3-1 advantage. Luke Maile walked with the bases loaded in the bottom of the seventh frame for the Blue Jays' second run.
Rafael Devers hit a solo shot in the top of the eighth inning for Boston, which was matched by a solo shot from the Blue Jays' Justin Smoak in the bottom of the inning. Danny Jansen tied the game with an RBI single for Toronto in the bottom of the ninth inning, sending the game to extra innings.
Mookie Betts appeared to give the Red Sox the win with a solo home run in the 12th inning, but Rowdy Tellez answered with a solo shot for Toronto in the bottom of the inning.
Michael Chavis provided the parting blow with a solo home run to center field in the top of the 13th inning, helping Boston improve to 26-23 on the season.
Guerrero is now hitting .253 with five homers and 11 RBIs on the season. The Red Sox battle the Blue Jays at 12:37 p.m. on Thursday in Toronto.