CINCINNATI -- Mitch Moreland hit a three-run home run and Eduardo Rodriguez allowed only three hits through 7 2/3 innings, lifting the Boston Red Sox to a 5-0 victory over the Cincinnati Reds on Saturday afternoon at Great American Ball Park.
The win reduced Boston's magic number to five to clinch the American League East title. The Red Sox (90-64) lead the New York Yankees by four games.
The Yankees, who clinched a wild-card berth on Friday, defeated Toronto 5-1 on Saturday.
Rodriguez (6-6) had six strikeouts and walked two. It was his longest outing since May 21. Rodriguez has made six straight quality starts on the road and four straight starts of two earned runs or fewer.
Cincinnati (66-89) committed two errors and had a passed ball while losing its fifth straight game.
Rookie right-hander Robert Stephenson (5-6) made his 10th start of the season for the Reds and was charged with two earned runs in six innings.
Xander Bogaerts led off Saturday's game with a double and advanced to third on a passed ball by Tucker Barnhart. Bogaerts scored on a sacrifice fly by Brock Holt to put the Red Sox ahead 1-0.
Rodriguez did not allow a hit until Joey Votto's single with one out in the fourth.
Boston's defense helped him out.
Votto was thrown out trying to reach second after his single by Andrew Benintendi.
It was Benintendi's 11th outfield assist this season, tying him for third in the American League.
Scooter Gennett singled leading off the fifth to extend his hitting streak to a season-high seven games. But, he was erased on an inning-ending 3-6-3 double play.
Stephenson's fielding error on Holt's grounder back to the mound opened the floodgates in the sixth.
Benintendi walked, then Moreland followed with a three-run blast to center, putting Boston ahead 4-0.
It was Moreland's 20th homer of the season, and it snapped a 0-for-19 skid.
Benintendi, a Cincinnati area native, prompted cheers from his hometown fans with an RBI single in the seventh to make the score 5-0.
Reds right-hander Luke Farrell, son of Red Sox manager John Farrell, pitched the ninth inning, marking the first time a major-league player has faced his manager father since the Chicago Cubs' Moises Alou faced his dad, Felipe's San Francisco Giants, in 2004.
Farrell walked two in a scoreless frame, then offered a subtle tip of his cap toward his dad in the dugout as he walked off.
NOTES: Boston Red Sox RF Mookie Betts was scratched from the lineup with a left foot contusion. Betts fouled a pitch off the top of his foot in his second at-bat on Friday, according to manager John Farrell. Brock Holt started in RF. Betts is expected back in the lineup on Sunday. ... Cincinnati Reds CF Billy Hamilton was given a day off on Saturday. He returned to the lineup Friday after missing 13 games with a fractured left thumb. ... The Reds honored RHP Bronson Arroyo prior to Saturday's game. He is retiring following the season after 14 seasons, including three with the Red Sox.