Only a select few players in Major League Baseball history can be definitively identified as the face of their franchise.

After spending all 21 seasons of his Hall of Fame career in Kansas City, George Brett is certainly qualifies for the Royals.

"With us, he was THE guy,” former teammate Willie Wilson said. “The bigger the situation, it's like the more fun he was having."

Brett’s tendency to breathe fire yet still manage to stay cool under pressure is explored in-depth in the new documentary “Brett” that premieres on MLB Network this Thursday at 8 p.m. ET.

Here are some of the top takeaways from the 90-minute feature:

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Brett’s competitiveness was legendary

The documentary features interviews with teammates, opponents and Brett himself – with his intensity on and off the field being a central theme.

"We knew that George took the game extremely seriously because we've seen him in action a few times when he wasn't the happiest guy in the world," recalls Milwaukee Brewers Hall of Famer Robin Yount in a bit of an understatement.

Yet the 13-time All-Star and three-time batting champion also knew how to enjoy playing the game.

"There are some players who do not want to be at home plate with the game on the line. George reveled in it, embraced it, loved it. And usually delivered," said longtime Royals radio announcer Denny Matthews.

"I always thought of myself as a clutch player," Brett admits. "The more nervous I was, the more clutch I was."

Brett’s complicated relationship with his dad

The competitive fire burned inside Brett from a young age, which the film explains originated in his rocky relationship with his father.

A military veteran, Jack Brett and his wife raised four sons. The oldest, Ken, went on to play 14 seasons in the major leagues as a pitcher.

As the youngest, George endured constant criticism from his father.

"I was intimidated by him my whole life," Brett says. "I couldn't do anything right."

Even after being named AL MVP in 1980 and nearly hitting .400, he struggled for Jack’s approval. After the season, he recalled the first thing his father said to him: “If you woulda taken better care of yourself you would've gotten five more hits."

Bad blood with the Yankees

The Royals faced off against the New York Yankees in the American League Championship Series four times in a five-year span from 1976-80.

That led to some strong feelings – on both sides.

"The rivalry was sportsman hate," said star outfielder Reggie Jackson, whose Yankees won each of the first three ALCS matchups.

"I was in baseball 49 years as a player and a coach. I've never seen intenseness like those two teams played. And we both knew it," said former Royals catcher Jamie Quirk.

The intensity boiled over in Game 5 of the 1977 ALCS when Brett hit a booming triple in his first at-bat and barreled into third base ahead of a tag attempt by the Yankees’ Graig Nettles.

"I slid late and my momentum took me over the bag,” Brett recalled. “As I came up, I kinda pushed Graig. He took offense to it and he just kicks me in the mouth with his left foot. I was like what the hell was that? And I just get up and I throw a haymaker at him."

Both benches emptied and a brawl ensued. But no one was ejected.

An interesting coda: Despite the bad blood, Brett says Yankee catcher Thurman Munson jumped on top of him in the scrum … to protect him.

“I'll never forget this: "He said, ‘George, it's Thurman. I got you covered. No one's gonna take any potshots at ya.'

“How cool was that?"

Brett’s untimely bout with hemorrhoids

The Royals finally broke through against the Yankees, beating them in the 1980 ALCS to advance to the World Series against the Philadelphia Phillies.

But Brett wasn't completely healthy, having developed a bad case of hemorrhoids on the eve of the Series opener.

He tried to play but couldn't make it through Game 2, eventually being replaced at third base by Dave Chalk.

After undergoing emergency surgery, Brett was back on the field for Game 3 in Kansas City, famously telling NBC sportscaster Bryant Gumbel, "My problem's behind me now."

In his first at-bat of the game, Brett hit a home run − becoming the first player in Kansas City Royals history to homer in a World Series game.

K.C. ended up losing the series to Mike Schmidt, Pete Rose, Steve Carlton and the Phillies. But Brett and the Royals would eventually get that elusive World Series title when they defeated the St. Louis Cardinals in seven games in 1985.

The 'Pine Tar Game'

Perhaps the most iconic moment of Brett’s 21-year MLB career came not during a playoff game, but a midseason contest against … who else? The Yankees.

On July 24, 1983, Brett stepped to the plate at Yankee Stadium with a runner on first base and the Royals trailing by a run with two outs in the top of the ninth.

On the mound was Yankees closer Goose Gossage, who three years earlier gave up a memorable three-run homer to Brett in Game 5 of the ALCS.

Gossage was as menacing as any pitcher of his day, but Brett wasn’t intimidated.

"Goose was the kind of guy I liked to face in that situation," he said.

Looking for a pitch on the inner half of the plate, Brett launched a high drive into the right field seats to put the Royals ahead by a run. But Yankee manager Billy Martin had noticed Brett – who famously never used batting gloves when he hit – had a significant amount of pine tar on the bat to help him with his grip.

Citing a little-known rule, Martin accused Brett of using an illegal bat. And after a lengthy discussion among the umpires, Brett was called out to end the game.

Brett erupted like never before.

"I thought I kinda walked out there and then I’d seen the video of it after it happened and my arms are going crazy ...” he recalled.

The Royals appealed and following a court order, the game was resumed 25 days later. The Royals finished off a 4-3 win by holding the Yankees scoreless in the bottom of the ninth.

But Brett wasn't in the ballpark since he was ejected for his tirade. He was at an Italian restaurant near LaGuardia airport watching the outcome "on a little black and white TV behind the bar."