ST. LOUIS — Aledmys Diaz made a vow Monday to the family of childhood friend Jose Fernandez, the late Miami Marlins ace who died in a boating accident early Sunday.

"I told them that every single time I put on the uniform, I would be thinking of him," Diaz said. "And that I would give 100 per cent because that's how he played the game."

Fernandez would have been proud of his longtime buddy on Tuesday night.

Back in the lineup after attending a private ceremony for Fernandez in Florida on Monday, Diaz hit his first career grand slam and the St. Louis Cardinals finished with five home runs in a 12-5 victory over the Cincinnati Reds.

St. Louis remained one game behind San Francisco for the final NL playoff spot, and 1 1/2 games behind the New York Mets.

The Giants routed Colorado 12-3. The Mets, who lead the wild-card standings, won 12-1 at Miami.

Jhonny Peralta had a three-run homer and drove in four runs for the Cardinals, who had lost four of five. Matt Carpenter, Randal Grichuk and Matt Adams also homered.

Joey Votto and Scott Schebler went deep for the Reds, who beat St. Louis 15-2 on Monday.

Diaz slammed a 2-1 pitch from Cincinnati starter Robert Stephenson over the left-field wall. The 408-foot drive erased a 2-1 deficit and served as a wake-up call for the Cardinals, who grabbed their first lead since Saturday.

The Cuban-born Diaz pointed to the sky after he crossed home plate and fell into the arms of teammate Yadier Molina. Diaz had tears in his eyes as he came out of the dugout for a curtain call.

"I felt some serious goose bumps when he hit that," Cardinals pitcher Adam Wainwright said. "I almost got choked up. I know he was. He wanted to make some good swings for Jose."

The emotional home run triggered an 11-run outburst in a span of three innings.

"Watching him cross the plate, and watching his reaction as he (shook hands) with the guys, really hit me on how much that meant to him," St. Louis manager Mike Matheny said. "You can never understand what each person's going through when they suffer a loss like that. The show goes on and so does life. But it's a tough thing for anyone to go through."

Stephenson (2-3) ended up allowing five runs in four innings.

Wainwright (13-9) gave up five runs and 10 hits over 5 2/3 innings.

Adams connected for a pinch-hit homer in the sixth, extending the franchise record to 16 this season.

St. Louis has hit an NL-leading 218 homers this year.

Carpenter hit his 20th home run, giving the Cardinals five players with 20 or more.

The Cardinals broke out of a hitting slump after scoring just three runs in their previous two games.

"There's no telling how big this could be," Wainwright said.

Votto was 3 for 5 and finished a triple shy of the cycle.

Stephenson rolled through the first three innings, giving up just a solo homer to Carpenter.

"I felt a lot better today, especially at the beginning of the game," Stephenson said. "I was a lot more under control. Just a nightmare inning in the fourth inning."

Stephenson was aware of Diaz's relationship with Fernandez.

"I thought that was real unfortunate timing for me," Stephenson said. "But really, a special moment for him."

TRAINER'S ROOM

Reds: SS Zack Cozart, who has not played since Sept. 10 due to a sore right knee, was placed on the disabled list and will not return this season. ... 2B Brandon Phillips left in the seventh after hurting his wrist when he checked his swing. He is day to day. ... Schebler had a cramping issue and was removed in the eighth.

Cardinals: Carpenter was back in the starting lineup after missing Monday's game with a right finger injury.

UP NEXT

Reds RHP Anthony DeSclafani (8-5, 3.38 ERA) faces RHP Mike Leake (9-11, 4.72) in the third game of the four-game series Wednesday. DeSclafani has 13 quality starts in 19 starts this season. Leake is 0-1 with an 8.31 ERA in three starts against his former team.