CINCINNATI -- The biggest cheer in any action movie doesn't come when the hero defeats the first dozen henchman who foolishly get in his way. No, that cheer comes when the hero faces his nemesis, takes all he can offer and still, somehow, emerges victorious.

For much of this season, the eighth inning has served as the nemesis of the Reds. But on Saturday night, the Reds finally took a hard blow in the dreaded eighth and still came out with a win, defeating the Diamondbacks, 5-4, at Great American Ball Park.

Cincinnati headed into the eighth inning ahead, 4-1, looking strong -- dominant, even. Cincinnati had held Arizona to just six hits over the 16 previous innings, and only two in Saturday's game.

But the Reds also entered the eighth having allowed 63 eighth-inning runs this season, while scoring only 36. They had already lost five games in which they had led after seven frames.

So when Eric Byrnes blasted a three-run home run off reliever Todd Coffey (his third blown save of the year) to tie the score at 4-4 in the top of the eighth, it seemed all but inevitable that the Reds would eventually lose the game.

But the Reds did not succumb to their eighth-inning misfortune. In the bottom of the frame, smart baserunning by Brandon Phillips put him in scoring position for Norris Hopper, whose RBI single drove him in to put Cincinnati ahead again, 5-4.

Closer David Weathers gave up a hit and a walk but held Arizona scoreless to seal the win in the top of the ninth for his 17th save of the year.

"'Here we go again with the eighth inning,'" interim manager Pete Mackanin said. "A little trouble, but we overcame it. We came back. Weathers did an unbelievable job. He really did a great job at the end."

The victory gave the Reds three consecutive wins for the fourth time this season. They last won three games in a row May 28-30.

Rookie starter Homer Bailey held the D-backs in check, giving up one earned run on just two hits with two walks and five strikeouts over five innings to take the no-decision. With the score at 2-1 in the Reds' favor, Mackanin pinch-hit for Bailey in the bottom of the fifth inning.

"Homer did a real nice job," Mackanin said. "He's got a revamped delivery. [Pitching coach] Dick Pole has been working on his delivery, some mechanical things, so we figured that after five innings, it's best to get him out on a positive note."

Bailey (2-2) said the team's newfound momentum (the Reds have won four of their past five games) set the tone for its eighth-inning rally.

"It's kind of funny how stuff like that starts," the rookie right-hander said. "You start getting on a role, you start getting those clutch hits, bullpen guys making great pitches, that's how you win baseball games.

"Here lately, we've been winning a lot of games, so when the momentum starts going, you really start seeing your true players."

One of the "true players" Bailey mentioned was reliever Mike Stanton, who pitched two clean innings of relief, retiring all six batters he faced in the sixth and seventh innings, to maintain the Reds' 4-1 lead. It was Stanton's first appearance since going on the disabled list on June 17 with a left hamstring injury.

Reliever Jon Coutlangus, who recorded all three eighth-inning outs after Coffey's departure, earned the win to improve to 4-1.

Edwin Encarnacion knocked in two of Cincinnati's four runs in the fifth inning with a two-run home run off D-backs starter Brandon Webb. Webb gave up four earned runs on five hits with two walks and eight strikeouts over seven innings to take his own no-decision.

Diamondbacks reliever Tony Pena (3-2), who gave up Hopper's RBI single, took the loss.

The Reds are now 4-1 under Mackanin, who managed his first game on Tuesday. Asked whether the credit is Mackanin's for the team's recent success, Stanton said the situation is more complex than that.

"I think we are playing with a little more energy," Stanton said. "Now is that Pete, or is it the fact that [former manager] Jerry [Narron] got fired? Because those are kind of two different things.

"You have to look at those as two different things. I don't know if it's one or the other. It very well might be both, but we do seem to be playing with a little bit better energy, a little bit more concentration, and that's really all it takes."

Reds rookie center fielder Josh Hamilton left the game in the middle of the second inning after spraining his right wrist while swinging a bat in the on-deck circle. He will have a cast put on the wrist until Thursday, when he will be re-examined by Reds medical director Dr. Timothy Kremchek.