BALTIMORE -- The moment wasn’t too big for Jackson Holliday. The 20-year-old has dreamt about delivering critical hits in baseball games since he was a toddler, and his disappointing debut stint in MLB didn’t even come close to shattering his confidence.

From the moment Holliday connected with this particular pitch on Wednesday afternoon, he knew his first big league home run -- a massive grand slam -- was about to be logged in the record books.

“That’s about as best as I can hit a ball,” said the Orioles’ second baseman and son of seven-time All-Star outfielder Matt Holliday. “That’s about all I got.”

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MLB Pipeline’s No. 1 overall prospect announced his return to the Majors with a Statcast-projected 439-foot slam in the fifth inning of Baltimore’s 10-4 win in the series finale vs. Toronto at Camden Yards. Holliday belted an 0-2 slider from Blue Jays right-hander Yerry Rodríguez, with the ball leaving the bat at 109.2 mph.

The gargantuan blast sailed over the right-field flag court and onto Eutaw Street, as Holliday (20 years, 240 days old) became the youngest player in franchise history to hit a grand slam.

It was the seventh Eutaw homer of the season, the fifth by an Orioles player. Of the 129 total home runs hit to Eutaw Street, only two have been a player’s first career homer, with Holliday joining the Astros’ Robbie Grossman, who achieved the feat exactly 11 years earlier on July 31, 2013.

“He’s got one more Eutaw Street home run than me. I was messing with him about that,” said outfielder Colton Cowser, who also went deep in the victory. “But yeah, really happy for him.”

Holliday is the third player in Orioles history (since 1954) to hit a grand slam for his first MLB home run, joining Frank Baker (Sept. 28, 1973) and Fritz Connally (April 19, 1985). He’s the eighth-youngest in AL/NL history to have his first homer be a slam, per the Elias Sports Bureau.

“It’s pretty surreal. Couldn’t have dreamt it up any better for a first home run,” said Holliday, the No. 1 overall pick in the 2022 MLB Draft. “It’s just exciting to be able to help the team win, you know? When I was struggling, I felt like I couldn’t really do that. But to be able to come through in a big spot is more important to me than anything else.”

Recalled from Triple-A Norfolk prior to the game, Holliday said in the morning that he felt “more prepared” heading into the start of his second MLB stint. His initial big league callup didn’t go as he -- or anybody else, for that matter -- expected, as he went 2-for-34 with a pair of singles and 18 strikeouts over 10 games from April 10-23.

Holliday dropped to 2-for-36 in his MLB career with groundouts in each of his first two plate appearances Wednesday before he stepped to the plate with the bases full in the fifth to face Rodríguez. Holliday fell behind, 0-2, before capitalizing on the mislocated slider and extending the Orioles’ lead to 8-3 with one swing.

“I know [his career] hasn’t started the way he wanted, but he’s the No. 1 prospect for a reason,” Toronto manager John Schneider said. “That’s what you do with a hanging breaking ball. That was an impressive swing.”

Added Baltimore skipper Brandon Hyde: “I thought his at-bats were much better.”

Holliday’s 1-for-5 day nearly featured a second home run, which would have been a three-run shot in the sixth. He lined an 0-1 fastball from right-hander Ryan Burr the opposite way to left field, and it went over the lower part of the left-field wall near the foul pole, but just to the left.

The O’s challenged the call, but it stood following a replay review.

“I knew I hit it all right, and I thought maybe it would fall, and then all of a sudden, it was over the wall,” Holliday said. “I didn’t think it was going to be anywhere close to being a home run, but I really wish it was. That would’ve been pretty awesome.”

Don’t get Holliday wrong, though. His first game back was still plenty awesome.

After Holliday rounded the bases and celebrated with his teammates at home plate for the first time as a big leaguer, he retreated to the dugout. But the crowd continued to roar loudly, so Gunnar Henderson encouraged him to go out for a curtain call.

Holliday popped back out, gave a quick tip of the cap and went back in. Later, after the game and prior to his on-field interview on MASN, Cowser and Henderson dumped a cooler of Gatorade on Holliday.

They were all memorable moments on a day that neither Holliday nor anybody else who was at Camden Yards will forget anytime soon.

“It’s always good to have teammates that are rooting for you. That’s special to me,” Holliday said. “And to have the fans there rooting you on, it’s very special.”