CINCINNATI -- The Reds called up catching prospect Tyler Stephenson on Sunday and pitching prospect Tejay Antone on Saturday. On Monday night vs. the Cubs, both players found themselves front and center in a game that had all the twists and turns of a theme-park ride.

“Exciting, nervous, emotions back and forth, kind of sad, then exciting, then sad again," Antone astutely summed it up.

Stephenson slugged a home run in his first Major League at-bat and Antone delivered 4 1/3 innings of important relief after starter Wade Miley didn't have it in his Reds debut. The outcome went down as an 8-7 loss for Cincinnati in the opener of a four-game series at Great American Ball Park.

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But the game was also a 6-0 deficit in the second inning before the Reds battled back.

"How about Antone and the way he pitched and the way he kept us in the game? Unbelievable job the first time out in his Major League debut," Reds manager David Bell said. "We lost the game, but it would be completely unfair without mentioning what an unbelievable job he did. And Tyler Stephenson and his Major League debut coming out, playing a huge part in almost pulling off a comeback win that we came up short on. And there’s no denying that [we lost], but these young players came up big tonight to give us an opportunity."

Cubs starter Jon Lester threw five innings of no-hit baseball but gave way to the bullpen after 76 pitches. It took seven relievers to finish the game while Antone held his own for the Reds. He hit the first batter he faced but found his footing when his first batter of the third inning, David Bote, was caught looking at a nasty 97 mph fastball for strike three.

"I was like, ‘OK, it’s the same game, same distance, nothing changes.’ I kind of settled in after that and I was ready to go," said Antone, the Reds’ No. 20 prospect per MLB Pipeline.

The 4 1/3 innings from Antone were the most by a Reds reliever in his debut since Rick Greene’s 5 2/3 innings on June 19, 1999, in a loss to Milwaukee in his only big league appearance. Antone's five strikeouts were the most by a Reds reliever in his debut since Ariel Hernandez had five K's vs. the Brewers on April 24, 2017.

Antone did not give up a hit until his last inning of work. After retiring seven in a row and eight of his last nine, he gave up Anthony Rizzo's two-out solo homer.

Chicago had an 8-1 lead in the bottom of the seventh. Stephenson, who replaced starter Curt Casali for the top of the inning, stepped up to bat against Cubs reliever Duane Underwood Jr.

"[Underwood] is actually a local Atlanta guy, so it's pretty funny how it all lined up, another local Atlanta guy that I'm facing for the first time," said Stephenson, a Georgia native and the Reds' No. 3 prospect. "Sure enough, he throws me a first-pitch curveball, and then I get a fastball out over the middle of the plate and I'm on time, I hit it. And after that, I don't know what happened. It's just pretty incredible."

The ball was projected to travel 421 feet and cleared the fence in center field. Bell said he hadn't given up on the game when he switched Stephenson for Casali, but the win probability wasn't in the Reds' favor.

"When we did [the change], we’re like, ‘Hey, yup, he’s probably going to hit a home run or something and help us come back and win,'" Bell said. "We just got lucky there. This guy can play, and he’s going to be a big part of this organization for a long time."

Stephenson was the first Reds player to homer in his first plate appearance since pinch-hitter Ted Tappe did it on Sept. 14, 1950, at Brooklyn. Clyde Vollmer is the only other Red to achieve the feat -- on May 31, 1942, at Pittsburgh.

In the eighth inning, Stephenson added a single, and he returned in the ninth to face closer Craig Kimbrel. The former Braves closer had walked the bases loaded and already forced in a run when he hit Freddy Galvis with a pitch.

"It was pretty surreal, obviously growing up and watching the Braves and everything and obviously he played with them and stuff," said Stephenson, who was needed for depth with Tucker Barnhart on paternity leave. "It was a pretty crazy moment, but you obviously have to forget about those things, especially since we had a chance to win it and stuff. That was on my mind."

Stephenson drew a one-out walk from Kimbrel to make it a one-run game. Jeremy Jeffress notched the final two outs -- including Joey Votto's sharp line drive to center field that ended the game.

Antone and Stephenson were paired often on their way up the Reds' system. Both were thrilled they could share a debut on the same day.

"We kind of joked saying we wish I would have come in earlier or he would have thrown later," Stephenson said.