Black picked Bruce, and the slugger made him pay.
Bruce hit a three-run homer with two out in the eighth inning to lift the Reds to a 5-3 victory over the Padres.
Pinch hitter Ramon Hernandez walked with one out and pinch runner Brandon Phillips moved to second on pinch hitter Edgar Renteria's short groundout to Spence. Votto was intentionally walked and Bruce responded with a drive into the seats in right for his 24th homer.
"I was thinking that's what I would do," Bruce said of the walk to Votto. "I had a pretty good idea he was going to throw me sliders."
Bruce also doubled in a run in the fourth for Cincinnati, which has won three straight games. Bill Bray (3-2) got the final out of the eighth, and Francisco Cordero pitched the ninth for his 23rd save.
Reds manager Dusty Baker tries to avoid placing lefty-batters Votto and Bruce next to each other in the lineup but felt he had no choice with Phillips unable to hit after being plunked on the elbow Tuesday.
"It was an uncomfortable situation for them and I've been there many times. It comes down to who do you want to face," Baker said.
Black had a decision to make. Bruce is 9 for 18 with three homers and 10 RBIs in his last five games, making the decision more difficult.
"You have to pick your poison," Black said. "Both are very good players. Votto's a great hitter. We chose to face Bruce and set up the force."
Mat Latos pitched seven effective innings for San Diego but had to settle for a no-decision. The right-hander gave up two runs and four hits, struck out five and walked one.
Bronson Arroyo made a pair of errors but pitched six effective innings for Cincinnati. The soft-tossing right-hander allowed two runs, one earned, and six hits. He also struck out six, walked two and hit a batter.
Arroyo strained his Achilles tendon covering first on the second play of the game.
"Bronson's a warrior. You have to drag him from the mound," Baker said.
Arroyo felt the pain but wanted to continue.
"It is sore but I felt that I would still have my command," Arroyo said. "I was just past the bag and had to reach back. That's how it happened. I was just concentrating on keeping the ball down."
The Padres grabbed the lead in the first, taking advantage of Arroyo's unusual error. Arroyo, last year's Gold Glove pitcher, missed first base and turned his right ankle on Jason Bartlett's one-out grounder to first baseman Votto.
Hundley, reinstated from the 15-day disabled list before the game, led off the second with a 406-foot home run to left-center field, his fourth of the season and first since April 17 at Houston.
Hundley was placed on the DL on July 8 with a right elbow strain that required arthroscopic surgery.
Reds SS Zack Cozart spent part of his 26th birthday on Friday undergoing Tommy John surgery on his left (non-throwing) elbow. He is expected to resume baseball activities in December and be 100 percent for spring training. ... Cairo's seventh-inning triple was the 1,000th hit of his career. ... The Padres optioned C Luis Martinez to Triple-A Tucson and sent RHP Ernesto Frieri to Tucson for a 30-day rehabilitation assignment. ... RHP Tim Stauffer, San Diego's starter on Saturday, is 2-0 with a 1.76 ERA in three games, two starts, at Great American Ball Park. ... RHP Homer Bailey, Cincinnati's scheduled starter, allowed five runs and six hits in three innings in a 10-7 loss to Colorado on Monday.