Miami ? The end for Roger Clemens will come a few hundred miles from where it all began in the minor leagues 20 years ago, pitching against a team that didn’t exist, in a ballpark that wasn’t built.

“I’ll be happy, yet I’ll be sad,” he said Tuesday, the look on his face alternating between boyish grin and melancholy. “I’m just grateful for this opportunity to be able to go out there again on the grandest stage.”

He made his final regular-season start last month, then had three games in the playoffs against Minnesota and Boston that could have been the end. Now, there are no more ifs.

Barring something unexpected, the Rocket will fire for the last time tonight, making his final major-league start when he pitches for the New York Yankees against the Florida Marlins in Game 4 of the World Series.

He is baseball’s only six-time Cy Young Award winner, his 310-160 record leaves him 17th on the career list and his 4,099 strikeouts place him third.

For a new generation of hot young arms, the 41-year-old is the shining example, showing how to work hard nearly every day, summer and winter, to keep the legs and upper body strong enough to fling fastballs past batters, some half his age.

“Yeah, I idolized him,” said 23-year-old Josh Beckett, Florida’s starter in Game 3. “I know when I was younger, I used to try to pitch like him and stuff — definitely in the street when we were playing home run derby.”

Clemens was drafted by the New York Mets out of high school in 1981 but went to the University of Texas. Two years later, he was taken by Boston with the 19th pick of the first round, turned pro and went to Winter Haven, Fla., a tall and lanky kid, not the burly hurler he became.

“It was pretty intimidating … pretty nerve-racking,” said the pitcher who turned into baseball’s premier intimidator.

By the following May 15, he was up with the Red Sox, making his major-league debut at Cleveland. He retired Brett Butler, his first batter, on a grounder, and got Mike Hargrove for his first strikeout.

While there wasn’t a big bang, a star was born.

The mound where he’ll make his final pitch was undeveloped land back then — ground wasn’t broken for what became Pro Player Stadium until Dec. 1, 1985. The Marlins didn’t even enter the National League until 1993.

His career was filled with famous moments, the 20-strikeout games against Seattle in 1986 and Detroit in 1996, the afternoon in 1990 that Terry Cooney ejected him from the AL championship series, the bizarre night at the 2000 World Series when he threw part of a shattered bat in front of Mike Piazza.

There were the 13 seasons he spent in Boston. Then, after then-Red Sox general manager Dan Duquette let him go, saying he was in his “twilight,” the two years in Toronto and the final five in New York. With the Yankees, he earned his first two World Series rings.

“It would be nice to cap that off with another ring,” he said, “because I think that’s what still drives me at this point. I know there’s guys in there that don’t have an opportunity to look down on their hand and see that world championship ring.”

Young players have gravitated to the nine-time All-Star. Andy Pettitte, his Texas neighbor, has become practically a brother.

“When you get a chance to know the human being, aside from the intimidating pitcher that we thought he was,” Yankees manager Joe Torre said, “you really appreciate what Roy Campanella said years ago: ‘You have to have a lot of little boy in you to play this game.’ He still is a little boy in a lot of ways.”

Clemens has gone out of his way to soak up the atmosphere in his final go-round, especially in the buildup to June 13, when he gained his 300th win and 4,000th strikeout on the same night at Yankee Stadium against St. Louis.

He’s taken the time to learn about all the famous players he’s passed. While he still might pitch for the United States in next year’s Athens Olympics, he says this year is it as far as his pro career.

“I’ll be sad because it’s my last game and to go out there and compete — I won’t have that. I won’t be able to do that,” he said.

Perhaps years from now, perhaps decades, pitchers will be passing him. He doesn’t mind that.

“I hope they have a smile or feel some kind of warmth,” he said, “like I did passing these guys.”