BOSTON (Interstat) — Vladimir Guerrero Jr. homered in the first inning, Nathan Lukes went deep in the seventh and the Toronto Blue Jays withstood a Boston Red Sox rally keyed by back-to-back homers in the eighth inning to win 4-3 on Thursday afternoon at Fenway Park.

Toronto completed a three-game sweep of the series, improving to 37-38 on the season. Boston fell to 29-43. The attendance was 32,027 and the game lasted 2 hours, 23 minutes.

Tommy Nance earned the victory for Toronto, his first win against two losses on the season. Mason Fluharty recorded his first save of the season. Aroldis Chapman took the loss for Boston, falling to 0-2. The Blue Jays outhit the Red Sox 10 to 5.

Guerrero Jr. gave Toronto a 1-0 lead in the top of the first inning when he launched a line drive home run to center field, his fourth homer of the season. The at-bat came after George Springer struck out swinging to open the game. After Guerrero Jr.’s homer, Jesus Sanchez grounded out, Yohendrick Pinango walked and Ernie Clement flied out to left fielder Jarren Duran to end the inning.

Boston went down in order in the bottom of the first. Mickey Gasper popped out to catcher Brandon Valenzuela in foul territory, Ceddanne Rafaela popped out to second baseman Ernie Clement and Wilyer Abreu struck out swinging.

Toronto added a run in the second inning. Nathan Lukes grounded out to first baseman Willson Contreras before Kazuma Okamoto doubled on a line drive to left fielder Jarren Duran. Brandon Valenzuela singled on a sharp line drive to right fielder Wilyer Abreu, sending Okamoto to third. Andres Gimenez then hit a sacrifice fly to left fielder Jarren Duran, scoring Okamoto and giving Toronto a 2-0 lead. George Springer doubled on a line drive to left fielder Jarren Duran, moving Valenzuela to third, but Vladimir Guerrero Jr. grounded out to second baseman Andruw Monasterio to end the inning.

Boston again went down in order in the bottom of the second. Willson Contreras grounded out to second baseman Ernie Clement, Jarren Duran struck out swinging and Isiah Kiner-Falefa popped out to second baseman Ernie Clement.

The third inning was scoreless for both teams. For Toronto, Jesus Sanchez flied out to center fielder Ceddanne Rafaela, Yohendrick Pinango popped out to third baseman Caleb Durbin and Ernie Clement lined out to left fielder Jarren Duran. For Boston, Caleb Durbin flied out to center fielder Nathan Lukes, Connor Wong struck out swinging and Andruw Monasterio struck out swinging.

The fourth inning saw Toronto go down in order as Nathan Lukes flied out to center fielder Ceddanne Rafaela, Kazuma Okamoto grounded out to third baseman Caleb Durbin and Brandon Valenzuela was called out on strikes. Boston threatened in the bottom of the fourth as Mickey Gasper hit a ground-rule double down the right-field line. Ceddanne Rafaela sacrificed bunted, moving Gasper to third, but Wilyer Abreu flied out to center fielder Nathan Lukes and Willson Contreras struck out swinging to end the inning.

The fifth inning was scoreless. For Toronto, Andres Gimenez grounded out to first baseman Willson Contreras, George Springer grounded out to shortstop Isiah Kiner-Falefa and Vladimir Guerrero Jr. grounded out to shortstop Isiah Kiner-Falefa. For Boston, Jarren Duran lined out sharply to right fielder Jesus Sanchez, Isiah Kiner-Falefa popped out to catcher Brandon Valenzuela in foul territory and Caleb Durbin popped out to second baseman Ernie Clement.

The sixth inning saw Toronto fail to score despite a baserunner. Jesus Sanchez singled on a ground ball to right fielder Wilyer Abreu. Yohendrick Pinango grounded out, moving Sanchez to second. Ernie Clement reached on a fielder’s choice as shortstop Isiah Kiner-Falefa threw to third baseman Caleb Durbin to tag out Sanchez. Nathan Lukes then came to the plate, but Ernie Clement was picked off and caught stealing second base by shortstop Isiah Kiner-Falefa. Boston went down in order in the bottom of the sixth as Connor Wong was called out on strikes, Andruw Monasterio popped out to first baseman Vladimir Guerrero Jr. in foul territory and Mickey Gasper flied out to center fielder Nathan Lukes.

The seventh inning proved pivotal. Nathan Lukes led off the top of the seventh with a home run on a line drive to right-center field, his second homer of the season, extending Toronto’s lead to 3-0. Kazuma Okamoto struck out on a foul tip, Brandon Valenzuela flied out to center fielder Ceddanne Rafaela and Andres Gimenez struck out swinging to end the inning.

Boston responded in the bottom of the seventh. Ceddanne Rafaela doubled on a ground ball to left fielder Yohendrick Pinango. Wilyer Abreu lined out to right fielder Jesus Sanchez, and Rafaela advanced to third. Willson Contreras grounded out to shortstop Andres Gimenez, scoring Rafaela and cutting Toronto’s lead to 3-1. Jarren Duran grounded out to pitcher Trey Yesavage to end the inning.

The eighth inning contained the most critical sequence of the game. Toronto had an opportunity to extend its lead in the top of the eighth. George Springer singled on a ground ball to right fielder Wilyer Abreu. Vladimir Guerrero Jr. flied out to right fielder Wilyer Abreu. Jesus Sanchez struck out swinging. Yohendrick Pinango doubled on a fly ball to center fielder Ceddanne Rafaela, but George Springer was thrown out at home plate on the throw from center fielder Ceddanne Rafaela to catcher Connor Wong, ending the inning and keeping the score 3-1.

Boston capitalized on that missed opportunity in the bottom of the eighth. Isiah Kiner-Falefa led off with a solo home run on a fly ball to left field, his second homer of the season, cutting Toronto’s lead to 3-2. Caleb Durbin followed with a solo home run on a fly ball to left-center field, his fourth homer of the season, tying the game 3-3. Connor Wong grounded out to shortstop Andres Gimenez. Andruw Monasterio flied out to right fielder Nathan Lukes. Mickey Gasper singled on a ground ball to shortstop Andres Gimenez. Ceddanne Rafaela grounded out to third baseman Kazuma Okamoto to end the inning, but the damage was done and the game was tied.

Toronto regained the lead in the top of the ninth. Ernie Clement singled on a soft ground ball to pitcher Aroldis Chapman to lead off the inning. Nathan Lukes bunt popped out to catcher Connor Wong in foul territory. Kazuma Okamoto struck out swinging. Brandon Valenzuela then doubled on a fly ball to left fielder Jarren Duran, scoring Ernie Clement and giving Toronto a 4-3 lead. Andres Gimenez popped out to second baseman Andruw Monasterio to end the inning.

Fluharty closed out the game for Toronto in the bottom of the ninth. Wilyer Abreu flied out to center fielder Myles Straw. Willson Contreras grounded out to third baseman Kazuma Okamoto. Jarren Duran popped out to third baseman Kazuma Okamoto to end the game and give Toronto the victory.

Sonny Gray started for Boston and pitched seven innings, allowing three earned runs on six hits with four strikeouts and no walks. Justin Slaten pitched one inning in relief, allowing no earned runs on two hits with one strikeout. Chapman took the loss, pitching one inning and allowing one earned run on two hits with one strikeout.

For Toronto, the win marked the third consecutive victory over Boston in this series, following a 3-0 win Wednesday and a 6-1 win Tuesday. The Blue Jays have won five of their last six games overall, with the only loss coming against the New York Yankees on June 13.

The Red Sox have lost four consecutive games and seven of their last nine. Boston’s most recent win before this series was a 10-1 victory over the Texas Rangers on June 12.

Toronto’s next game is Friday at the Chicago Cubs. Boston travels to Seattle for a series against the Mariners beginning Friday.

Interstat’s game simulator had projected a final score of Toronto Blue Jays 5, Boston Red Sox 3. Interstat’s ELO system had projected Toronto with a 50.10 percent probability to win. Toronto had been installed as a pregame favorite with a spread of -1.5. The total score of 7 went over the over/under line of 8.5.