"There are guys who throw a soft 100 mph fastball -- you can see it coming and you can time it," Tigers catcher James McCann said. "Hicks is throwing a hard 103. It is right on top of you, and it moves. It's tough to make contact, and he barreled it up."
Hicks, who was facing his sixth batter, gave Candelario most of the credit.
"I was sharp and I was trying to pound the strike zone," he said. "He just got good wood on it and the ball left the yard. I can't mourn a mistake. I just have to get better."
Candelario's second career game-ending homer was made more special by the presence of his family.
"This is a blast," he said in a postgame television interview. "To do this, not just in front of the fans, but in front of my family."
Marcell Ozuna homered twice for St. Louis, which has lost four of six. The Cardinals hold a slim lead for the second NL wild-card spot.
"I'm trying to be more aggressive," Ozuna said. "When my shoulder was hurting, I couldn't stay inside, but now I feel better and I can hit that pitch."
The Tigers won their third in a row.
"That's a lot of fun," manager Ron Gardenhire said. "Those guys are in a pennant race and we're not, but we stepped up and got a victory. Those are the moments you enjoy."
Hicks (3-4) retired the first five batters he faced, but rookie Victor Reyes slapped a 102 mph fastball to left with one out in the ninth, and Candelario hit his 18th homer on the next pitch.
"Candy is still learning at this level, but he's a strong young man," Gardenhire said. "He has some tough at-bats, but he can also do that."
Detroit closer Shane Greene (3-6) worked a scoreless ninth.
Tigers starter Daniel Norris allowed three runs on four hits and a walk in five innings. He struck out seven and gave up both of Ozuna's homers.
"I learned not to throw him a fastball over the plate," he said.
Norris was making his second start after missing four months with groin surgery and was starting at home for the first time since April 20.
"It was great to be out there in front of our fans, wearing our white jerseys and feeling healthy," he said. "It's been a long road back."
Cardinals starter Austin Gomber gave up three runs on six hits and three walks in six-plus innings, striking out six.
Ozuna led off the second with a home run, much to the delight of the large contingent of Cardinals fans. The Tigers made it 1-all in the bottom of the inning on Dawel Lugo's RBI groundout.
Ozuna connected for his 20th homer to begin the fourth. He also hit two home runs against Washington on Tuesday.
Gomber retired the first two batters in the bottom half, but Reyes beat out a bunt single and the Tigers loaded the bases on Candelario's base hit and Goodrum's walk. Nicholas Castellanos lined a tying, two-run single.
Cardinals: C Yadier Molina is expected to miss the three-game series in Detroit with a hamstring injury.
REYES KEEPS IMPROVING
Reyes, a Rule 5 pick who had never played above Double-A ball before this season, was hitting .118 with no walks or extra-base hits after the first 25 games of his career. Since then, playing more regularly, he is batting .261 in 60 games and hit his first career homer last week in New York.
"Once I gave him a chance, he's worked hard to become a major league player, and we expect him to stay here next year," Gardenhire said.
The Tigers are celebrating the 50th anniversary of their 1968 World Series win over the Cardinals during the weekend series. Five players from the 1968 team threw out first pitches on Friday, and a ceremony will be held before Saturday's game.
MLB's next big thing: Mauer's Hall of Fame case and more
Joe Mauer is a legend in Minnesota, but is he Cooperstown-worthy? We examine his Hall chances along with other recently retired stars.
With best years behind them, Giants face tough task of starting over
After two losing seasons and with their core players beyond their prime years, the horizon for the champs of 2010, '12 and '14 is bleak.
Japan confident for 2020 Games after win over MLB All-Stars
A 5-1 exhibition series win over the MLB All-Stars has given Japan every reason to be confident about its chances to win its first Olympic gold medal in baseball in 2020.
MVP Betts plans to improve consistency in offseason
Even after winning MVP, Mookie Betts is focusing on improving his offensive consistency in the offseason.
Veteran catcher Jeff Mathis agrees to two-year deal with Rangers
Jeff Mathis, one of the top defensive catchers in the majors, has agreed to a two-year deal with the Rangers, according to The Athletic.
Yelich: 'Unbelievable feeling' being named NL MVP
Christian Yelich joins SportsCenter after being named the National League MVP and receiving 29 of 30 first-place votes.