CINCINNATI -- Mitch Moreland gave a masterful Eduardo Rodriguez some breathing room with a towering three-run homer in the sixth and the Red Sox whittled their magic number down to five in the American League East with a 5-0 victory over the Reds on Saturday afternoon at Great American Ball Park.

Rodriguez (6-6, 3.91 ERA) was sharp from the outset en route to his fourth straight strong performance, holding the Reds to three hits over 7 2/3 scoreless innings and striking out six.

"I was was able to throw my fastball right where I wanted it almost all the time," said Rodriguez. "And the slider was working really good today."

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With eight games left, Boston (90-64) has a four-game lead in the division after the Yankees beat the Blue Jays on Saturday.

Not only was Red Sox manager John Farrell pleased with the win, but he got to experience the joy of watching his son pitch. Luke Farrell pitched a scoreless ninth inning for Cincinnati. According to Elias, it is the first time in history a pitcher faced a father as manager. The last time a player competed against a team managed by his father was Moises Alou, playing for the Cubs, against Felipe, managing the Giants, in 2004.

"That's a lot of people that have played this game," John Farrell said. "If that's the first combination, if it's denoted as the first, it's a proud day, and that makes it even that much more unique. Like I said, a class move by [Reds manager] Bryan [Price] to put him in the game.

"You know what? He's earned his way and we'll see what unfolds and transpires through the course of time. Just very proud to watch him on a Major League mound."

Clinging to a 1-0 lead in the sixth, Moreland changed the game when he unloaded on a first-pitch changeup from Robert Stephenson and smashed it with an exit velocity of 104.9 mph, according to Statcast™. Moreland's 20th homer of the season traveled a projected distance of 411 feet. Moreland has now hit at least 20 home runs in four consecutive seasons.

"He threw a changeup, split the plate in half, top of the zone there," said Moreland. "I was able to get the barrel to it. Just one of those where I'm trying to make something happen, especially with a couple of guys on there. So it was a good win for us."

The Red Sox got a sacrifice fly from Brock Holt in the top of the first to take the lead. That run was set up on a double by Xander Bogaerts and a passed ball by Reds catcher Tucker Barnhart.

Stephenson went six innings for the Reds, allowing five hits and four runs, just two of which were earned. He walked two and struck out four. Before the big inning, he was having a strong outing and throwing strikes. Of his 57 pitches through five innings, only 17 were balls.

"Everything was going really well. He had a soft double, a passed ball and a sacrifice fly to score the first run," Price said. "From that point on, it was really some shutdown pitching."

MOMENTS THAT MATTERED

Stephenson error opens floodgates: Stephenson had been cruising and looked like he was going keep it going when Holt led off the sixth by hitting a 65-mph tapper back to the box. But Stephenson muffed the routine play, and Holt beat it out. After that came a walk to Andrew Benintendi and the game-breaking homer by Moreland.

"I felt like I was pretty upset with myself after that and I lost focus for a little bit," Stephenson said. "I walked the next hitter and then left a split up to Moreland and he did what he was supposed to do with it."

Hometown hero adds insurance: With countless friends and family members at Great American Ball Park to cheer him on for the second straight day, Benintendi -- the pride of Madeira, Ohio -- belted an RBI single to left to open Boston's lead to 5-0 in the seventh. It was Benintendi's first hit of the weekend.

QUOTABLE

"In terms of efficiency, that was probably one of the best games I've thrown this year -- up to that point -- just being able to throw a lot of strikes. Their team was pretty aggressive, and they helped me get a lot of quick outs." -- Stephenson

"Well, that's something we had to clear up. He's not going to win a batting title, so Eddie took it upon himself to have a surprise attack." -- John Farrell, on Rodriguez trying to bunt his way on with two outs in the second inning

SOUND SMART WITH YOUR FRIENDS

Barnhart made his 100th start on Saturday, giving the Reds nine players who have made at least 100 starts this season, according to the Elias Sports Bureau.

The Red Sox are in strong position to win the AL East for the second straight season. It would mark the first time in club history Boston has won back-to-back division titles.

WHAT'S NEXT

Red Sox: Right-hander Doug Fister, who has struggled mightily in his last two starts, will try to get back on track when he starts Sunday's 1:10 p.m. ET finale against the Reds at Great American Ball Park. Fister has thrived against Cincy in his career, going 2-0 with a 1.35 ERA in three starts.

Reds: Cincinnati will look to rookie Jackson Stephens to help them avoid the sweep when he starts the Reds' home finale on Sunday. Stephens will make his third big league start and work his sixth game overall. In Tuesday's 8-7 loss in the 10 innings to the Cardinals, in which he got a no-decision, Stephens retired the first 10 batters before allowing five runs in the fourth inning -- including back-to-back home runs.