WASHINGTON — Over-hyped? Are you kidding? Stephen Strasburg went beyond the hype — and anyone’s reasonable expectations — by striking out 14 batters in his electric major league debut.

With a standing-room-only crowd cheering at every chance, the Washington Nationals phenom put on a dazzling display of power pitching Tuesday night in a 5-2 win over the Pittsburgh Pirates. His fastballs reached 100 mph, and batters found his nasty curves nearly impossible to hit.

“I just wanted to go out and soak up everything. It only happens once and I’ve been waiting for this my whole life,” Strasburg said.

Last year’s No. 1 overall draft pick — the one with the record $15.1 million contract — threw his first pitch 97 mph and got stronger as the game progressed. He struck out the last seven batters he faced, and all nine Pirates in the starting lineup fanned at least once.

The 21-year-old right-hander was pulled after seven innings and took a curtain call. He allowed four hits, two earned runs and didn’t walk a batter, piling up the most strikeouts in a big league debut since J.R. Richard fanned 15 for Houston in 1971.

Karl Spooner also struck out 15 in his debut with the Brooklyn Dodgers in 1954. He and Richard are the only pitchers with more strikeouts than Strasburg in a major league debut since 1920 — and Spooner and Richard both had three walks.

Strasburg also tied Max Scherzer of the Detroit Tigers for most strikeouts in a game in the majors this season. Scherzer had 14 on May 30 against Oakland.

Strasburg was removed for a pinch hitter in the bottom of the seventh with a 4-2 lead. When it was announced that he had set a team record for strikeouts since the franchise’s move to Washington in 2005, the crowd roared again — and Strasburg emerged to the top step of the dugout and tipped his cap.

During a postgame interview, Strasburg was pelted with a shaving cream pie to the face courtesy of teammate John Lannan. The rookie was quickly handed a towel, but after wiping his face was blindsided by two more pies. Someone also put a goofy, oversized wig on his head.

“It’s hard to talk with so much shaving cream on my head,” Strasburg said. “I just wanted to go out there and say I’ve had my first outing in the big leagues. I’ve had a great time.”

He threw 94 pitches — roughly the limit imposed by management before the game — and 65 were strikes. He made one noticeable mistake, a 90 mph changeup golfed by Delwyn Young into the first row in right field for a two-run homer in the fourth inning. The ball would have made a great souvenir, but a fan threw it back onto the field.

The homer gave the Pirates a 2-1 lead, but the Nationals put their rookie in position to win with three runs in the sixth. Adam Dunn hit a two-run homer, and Josh Willingham followed with a solo shot, allowing Strasburg to leave the game with a two-run lead.

Tyler Clippard pitched the eighth and Matt Capps the ninth for his 19th save.

Ryan Zimmerman also homered for the Nationals, another solo shot in the first inning. All three of Washington’s home runs came off Pirates starter Jeff Karstens (1-2).

The day was nicknamed “Strasmus” — and it was the biggest baseball event in the nation’s capital since the sport returned in 2005 after a 33-year absence. To go real deep into history, one could argue that Strasburg had the most anticipated Washington rookie pitching debut since Walter Johnson at the long-forgotten American League Park on Aug. 2, 1907.

Cameras flashed as Strasburg (1-0) threw his first pitch at 7:06 p.m. — well inside to leadoff hitter Andrew McCutchen. Fans booed when umpire Tom Hallion called it a ball.

Nationals catcher Ivan Rodriguez then handed the ball to Hallion and it was removed from play for posterity.

“I remember the adrenaline flowing about 2 o’clock,” Strasburg said.

McCutchen lined out to shortstop on a 2-0 pitch. Strasburg then got Neil Walker on a grounder to first and struck out Lastings Milledge with a pair of wicked curveballs for a 1-2-3 inning.

Only one Pirates batter reached against Strasburg in the first three innings. In the fourth, Strasburg allowed back-to-back singles. One of the runners was erased by a double play, but Young followed with his third homer of the season.

Strasburg was promoted after dominating the minors, going 7-2 with a 1.30 ERA, 65 strikeouts and only 13 walks in 11 starts in Double-A and Triple-A. His debut came nearly a year to the day after he was drafted No. 1 overall, and one day after the Nationals — who have lost 100 games in consecutive seasons — chose 17-year-old hitting sensation Bryce Harper with the No. 1 overall selection in this year’s draft.

Strasburg is a low-key kid in a high-hype world, a focused youngster whose fastball is much more lively than his news conferences. He quietly went about his business preparing to take the mound, fiddling with his glove a few hours before the game at his new locker, located between those of Wil Nieves and J.D. Martin.

Washington sold out Nationals Park for only the second time all season, and went through an extra 2,000 standing-room-only tickets a few hours before the game. Fans cheered when Strasburg emerged from the dugout at 6:24 p.m. with pitching coach Steve McCatty. Surrounded by photographers and cameramen, Strasburg grinned at McCatty and said, “Let’s go.”

Strasburg used the center-field wall to do some stretching and then warmed up in the bullpen, where fans stood six-deep to watch. He received a standing ovation when he walked back to the dugout after the national anthem, and it was a funny moment when McCatty — not Strasburg — doffed his cap to acknowledge the cheers.

Among those in attendance was Strasburg’s coach at San Diego State, Hall of Famer Tony Gwynn.

“Just a great night of baseball in Washington. He’s got that behind him,” Nationals manager Jim Riggleman said.

Asked what he told the rookie before the game, Riggleman said he asked Strasburg the distance from the mound to home plate in the minors.

When Strasburg answered 60 feet, 6 inches, Riggleman said: “You’ve got a good chance — because that’s what it is here, too.”

Rodriguez, a 20-year big league veteran, was activated from the 15-day disabled list in time to catch the game.

“He knows what day it is,” Riggleman said.

NOTES: Pittsburgh’s bench was thin. Pirates C Ryan Doumit was out with concussion-like symptoms. INF Bobby Crosby had a stomach virus. Doumit will likely miss two or three games, manager John Russell said. … Strasburg took his first professional defeat against Pittsburgh’s Double-A affiliate, Altoona on May 2. … RHP Brad Lincoln, the No. 4 overall pick in the 2006 draft, will make his major league debut as the Pirates’ starter on Wednesday.