SAN DIEGO -- In one ninth inning on Thursday night, Reds rookies pretty much experienced just about every emotion a thrilling Major League Baseball game can offer. Tension, excitement, pressure, the elation of coming through in a huge moment and the deflation of seeing it all slip away a few moments later.

The Reds battled down to their last out in the top of the ninth inning. Rookie catcher Tyler Stephenson had a game-tying, pinch-hit RBI single and Jonathan India delivered a go-ahead two-run home run. In the bottom of the ninth, a shorthanded bullpen gave up a pair of home runs for a 6-4 walk-off loss before a euphoric and loud sold-out crowd at Petco Park.

• Box score

“Gut punch,” said Stephenson, who stayed in on defense after his pinch at-bat. “It sucks just because, obviously, it’s under my control. Obviously, I take it personal, just as a catcher. It’s tough, just from how we fought back and just the emotions.”

The loss snapped Cincinnati’s six-game winning streak.

“Baseball doesn’t love you. It’ll come back and bite you, and it did,” India said. “But there’s nothing you can do. Those guys put good swings on good pitches tonight. They won the game.”

Reds starter Wade Miley held San Diego hitless for 5 2/3 innings. The first two hits Miley allowed were homers -- Fernando Tatis Jr. slugged one to left-center field in the sixth inning to break up the no-hitter and shutout bids. Manny Machado led off the seventh inning with his own homer to make it a 2-0 game.

“Good baseball game, man,” said Miley, who pitched into the eighth inning. “It was fun to be part of that game. It sucks that we were on the wrong end of it. At the end of the day, if you're a fan of baseball, that's a cool one.”

The Reds’ ninth-inning rally came against Mark Melancon, the National League’s co-leader in saves. Joey Votto led off with a single, and Tucker Barnhart doubled with one out. Kyle Farmer’s groundout plated Votto with Cincinnati’s first run.

Pinch-hitting with two outs and in a 0-2 count, Stephenson battled back to a full count before hitting his single into center field to tie the game.

“Just kind of erased the noise, and it’s the same baseball game that we’ve been playing for years,” Stephenson said. “So go back to the fundamentals and simplify it, try your best.”

The crowd of 40,362 went from cheering for the final strikes to actually quiet as Stephenson reached safely. India followed by hitting Melancon’s next pitch into the left-field seats for his sixth home run of the season.

“It’s amazing. For me and Tyler, we’ve been grinding all year,” India said. “The thing is, our team doesn’t make us feel like we’re rookies. We feel like we’ve been a part of this team for a while. Credit to our team: I think that’s what helped us so much. We feel comfortable in those situations, and our teammates trust us. They know we can get the job done, and we did.”

India even took a page from Tatis’ routine by doing a “hop-skip” ahead of third base while in his home run trot. That was planned.

“Tatis, he’s a great player, and you try it out a little bit and see what he does,” India said. “I tried it, I don’t think I did good, though.”

The good times did not last, however.

Manager David Bell’s bullpen was thinner than usual. Both Lucas Sims and Heath Hembree were unavailable after working three of the previous four games. Tejay Antone is still on the injured list with a forearm injury. Bell turned to another rookie in reliever Ryan Hendrix for his first big league save opportunity.

A leadoff four-pitch walk to Manny Machado opened the door for San Diego, and a two-run home run by Eric Hosmer tied the game. Amir Garrett replaced Hendrix and saw his first batter, Jake Cronenworth, hit a single into center field. The next batter, Victor Caratini, followed with the walk-off two-run home run.

“We were giving Ryan the first three hitters of the inning,” Bell said. “If he goes 1-2-3 and gets it done, great. Otherwise, we had Amir behind him.

“Ryan Hendrix is going to get that opportunity many more times in his career. So is Amir. We just went up against a good team, good hitters. They came through just like we did.”

• Garrett: 'You can never outrun adversity'

It was the first time since May 19, 1960, that Cincinnati tied a game while down to its last strike, and then immediately took the lead in the very next at-bat -- against Dodgers great Sandy Koufax. The last time the Reds gave up the game-tying and walk-off homers in the same inning was May 19, 2013, when Aroldis Chapman surrendered them -- back to back at Philadelphia.

“What a great baseball game to be a part of. It felt very similar to a playoff game,” Bell said. “Our guys came through all night, especially there late. Even though we lost the game, which was obviously disappointing, it was just a great experience, a great game for our team to be a part of.”