Ken Griffey Jr. and Ken Griffey Sr. hit 782 home runs between them in their careers. But the two that came on this date in 1990 produced one of the most special moments in MLB history.

On Sept. 14, 1990, the Griffeys hit back-to-back home runs for the Mariners. They became the first -- and still the only -- father-son duo to hit back-to-back home runs in a Major League game.

Here's how it all happened.

The background

Griffey Jr. made his MLB debut for the Mariners as a 19-year-old on Opening Day 1989. By that time, his father was about to turn 39 and was entering his 17th season in the big leagues. He was playing for the Reds, the team where he started his career in 1973 -- and where his son would end up a little over a decade later.

Junior was an instant sensation in Seattle, while his father was nearing the end of his career. On Aug. 24, 1990, a little over a month after Griffey Jr. became an All-Star for the first time, the Reds released Griffey Sr.

Five days later, on Aug. 29, he signed with the Mariners, and the Griffeys were teammates.

Reunion in Seattle

On Aug. 31, 1990, the 40-year-old Griffey Sr. and the 20-year-old Griffey Jr. became the first father and son to play as teammates in an MLB game.

"Here he is, a father, a veteran player ending his career, and the son is a brilliant young talent, just like his father was when he was first starting his career, and they’re both going to be out there together," Mariners manager Jim Lefebvre said before the game, per the Los Angeles Times. "Today is a great day for baseball. It’s a great day for Seattle. It’s a great day for the Mariners."

Playing at the Kingdome against the Royals, Griffey Sr. batted second for Seattle, and Griffey Jr. hit third right behind him. Griffey Sr. played left field; Griffey Jr. was beside him in center.

In the first inning, both Griffeys lined singles in their first at-bat.

"Being a father, I guess it's a dream come true," Griffey Sr. said at the time, according to the Washington Post. "This is the pinnacle -- this is the thing in my career that I’m very proud of -- very proud of. You can talk about the '76 batting race I was in and all that. But to me this is No. 1."

Back-to-back home runs

The Griffeys simply taking the field together was historic. Notching hits to start off their very first game together was even better. But they topped it all two weeks later.

In their first two weeks as teammates, both Griffeys hit home runs, but always in different games -- Griffey Sr. on Sept. 7 and 10, Griffey Jr. on Sept. 12.

On Sept. 14, though, the magic happened.

The Mariners had just left Seattle to play a series against the Angels in Anaheim. The series opener was a Friday night game at Anaheim Stadium with 34,180 fans in attendance. Griffey Sr. and Griffey Jr. were once again batting second and third in the Mariners' order.

In the top of the first inning, Griffey Sr. came up with a man on and no outs after a leadoff walk to Harold Reynolds, facing Angels starter Kirk McCaskill.

On an 0-2 count, he got a hanger over the outside part of the plate and lined it deep to center field, just over the glove of a leaping Devon White at the wall for a home run.

"He hit the home run, he's running around the bases, and I'm just looking at him," Griffey Jr. recalled years later. "He touches home plate, and he says: 'That's how you do it son.' And runs off!"

Junior high-fived his dad as he crossed the plate. Then he stepped in himself. And he went deep, too.

"I could see it in his eyes," Griffey Sr. remembered. "The determination he had, that he was gonna try to hit a home run."

With one of the most iconic swings in baseball history, Griffey Jr. crushed a low-and-away fastball way out to left for an opposite-field home run. Back-to-back home runs for the Griffeys -- another history-making father-son moment.

"What else can these guys do?!" said Joe Morgan on the TV broadcast.

Griffey Sr. grinned at his son from the other end of the dugout as Junior returned from his home run trot and made his way along the Mariners bench, high-fiving his teammates -- and finally his dad.

"I hit mine, I couldn't wait to get in the dugout," Griffey Jr. said. "When I got in the dugout, he made sure I shook everybody's hand first … and then he came up to me and gave me a hug."

"You know what we just did?" Griffey Sr. asked his son.

"You hit a home run … I hit a home run," Griffey Jr. replied.

"Yeah," his dad answered, "but it's back to back."

As cool as everything else the Griffeys did on the field together was, this moment has to be the most memorable. It was a unique moment in baseball history, and a special family moment for Griffey Jr. and Sr.

"It was just the smile on his face," Griffey Jr. remembered. "He was a dad the whole time."