CINCINNATI -- The Miami Marlins have had plenty of quality young pitchers in their history, but Justin Nicolino did something on Saturday night that none of them, including Josh Beckett and Brad Penny, had done.

Nicolino became the first Marlins pitcher to throw seven shutout innings in his major-league debut, and third baseman Derek Dietrich homered twice, lifting Miami to a 5-0 victory over the Cincinnati Reds at Great American Ball Park.

"For a guy to show that kind of presence in his major-league debut was tremendous," Miami manager Dan Jennings said. "Really impressive."

The left-handed Nicolino (1-0) was recalled from Triple-A New Orleans when right-hander Tom Koehler was scratched from his start because of neck and back soreness.

Nicolino shook off early nerves to allow just four hits in seven innings.

"It's indescribable," he said. "Before the first pitch, stepping on the mound, I realized where I was at. It was kind of hard to believe. But once I got that first pitch out of the way, it was the same game."

Dietrich, who came in 0-for-8 on the road trip, hit a solo homer in the fourth off Reds starter Anthony DeSclafani and added a two-run shot in the seventh off left-hander Manny Parra for his first career multi-homer game.

Dietrich went 2-for-2 with a walk, two homers and three RBIs.

"Tremendous night swinging the bat," Jennings said. "Gave us the power we've been looking for."

DeSclafani (5-5) and Nicolino were roommates last year at Class A Jupiter and Double-A Jacksonville and both part of the 12-player trade between the Marlins and the Toronto Blue Jays in 2012.

"When I found out, I wanted to call him right away," Nicolino said. "How much better would it be to debut against one of your best friends?"

They dueled pitch for pitch through the first three innings before Miami (30-40) scored three runs in the fourth en route to their fifth win over Cincinnati (31-36) in the last 16 meetings.

Nicolino induced three ground-ball double plays, helping him match the longest outing in a major-league debut for the Marlins since Penny in 2000.

Cincinnati was shut out for the fifth time this season.

"Nicolino pitched a nice game," Reds manager Bryan Price said. "We didn't put a lot of balls on the barrel. Give him credit. We found out at 2:30-3:00 that they were making the switch. It was before batting practice. It wouldn't have changed our lineup at all."

The Marlins held back Nicolino to keep him fresh in case Koehler missed time. The move paid off when Nicolino, who hadn't pitched since June 13, needed just 84 pitches to get through seven innings.

"He made some great pitches with his fastball on the inner half, and that opened up both sides of that plate for him," Jennings said.

Nicolino didn't allow a hit until Marcell Ozuna stumbled in center field, allowing DeSclafani's blooper to fall in for a single leading off the third.

"I think he was mad at me. He kind of stared at me when I was on base," DeSclafani said. "I'm happy for him. I know how hard he's worked."

Cincinnati had runners on first and second with none out, but Nicolino got second baseman Brandon Phillips to ground into a double play before striking out first baseman Joey Votto to end the inning.

"That was a big out," Nicolino said. "He's a great hitter."

Miami's first hit off DeSclafani came in the fourth when Dietrich launched his 1-0 pitch an estimated 439 feet into the right-field seats for his second home run of the season and the first run of the game.

"DeSclafani made some pitches he'd like to have back," Price said. "I didn't think he was on top of his game."

The Marlins pushed across three runs in the fourth, one on catcher J.T. Realmuto's RBI double to make it 3-0.

DeSclafani left after throwing 86 pitches in five innings and allowing three runs and four hits.

As for Nicolino, Koehler's health will determine how long he remains in the big leagues.

"That creates some tough decisions," Jennings said. "These are good problems to have. It's a good position to be in."

NOTES: Marlins RHP Tom Koehler was scratched because of neck and back pain. ... LHP Justin Nicolino made his major-league debut. He was acquired along with Reds RHP Anthony DeSclafani, whom he faced on Saturday, in a 12-player deal with the Toronto Blue Jays in 2012. ... Marlins C Johnathan Solano was designated for assignment. Miami was carrying three catchers, with J.T. Realmuto now healthy. ... Reds manager Bryan Price expects LHP Tony Cingrani (shoulder) and RHP Raisel Iglesias (oblique) to be back by the All-Star break. ... Reds C Devin Mesoraco will undergo season-ending hip surgery on June 29.