WASHINGTON — The coronation of a rivalry arrived with a 93-m.p.h. first-inning fastball off the small of Bryce Harper's back Sunday night on national television. Two days earlier when the Phillies arrived here, they filtered into the visiting dugout as the Nationals took batting practice. "Is Babe Ruth hitting?" one player mockingly asked.

Cole Hamels would not say when he decided to hit Harper, the teenager who has captivated all of baseball and the latest source of optimism in the nation's capital. He had done nothing specific to merit a plunking. But the Phillies certainly heard proclamations from Washington's players dismissing the five-time National League East champions before Sunday's 9-3 victory to salvage a weekend. So a message was sent.

"I'm not going to injure a guy," Hamels said. "They're probably not going to like me for it. But I'm not going to lie and say I wasn't trying to do it."

Two hours and 54 minutes of baseball Sunday produced a Phillies win and the signature moment in a rivalry so unavoidable. The Phillies, benchmarks for National League excellence, entered the day in last place while the Nationals were first and resemble the Phillies in their infancy of success. Fifteen more games between these two teams remain.

"It could be a really good rivalry," said Hamels, who dazzled in eight innings. "We're so close. Our fans can drive down, their fans can drive up. Their team is starting to peak into a really good competitive team."

For all the optimism two days plus a Harper steal of home had provided Washington, the Phillies at least boarded a train home with some confidence. They trail the Nationals by 4.5 games and will face them again in three weeks at Citizens Bank Park.

"Usually, it seems that the Phillies aren't that hyped up to come play us," Nationals shortstop Ian Desmond said. "I think they realized that they needed to step up a little bit, and that's nice."

Washington's enthusiasm was dimmed not only with the defeat, but when Jayson Werth hurriedly left the field with an injury later revealed as a broken left wrist. The $126 million outfielder will miss at least six weeks and quite possibly much more. The replays were almost too gruesome to watch. Werth dove for a Placido Polanco lazy fly to right in the sixth and his arm bent backward. Werth once injured his left wrist so badly he believed it would end his career.

Even then, this night will not be remembered for Werth's misfortune, Hunter Pence's home runs, or the "Let's Go Phillies!" chants when it ended.

With two outs in the first, Hamels fired the fastball at Harper in a spot where pitchers typically throw at someone on purpose. Harper crouched over and did not look at Hamels as he trotted to first. The majority of the crowd was Nationals fans and they booed.

"He's a great guy, great pitcher and knows how to pitch," Harper said. "He's an All-Star. It's all good."

The Phillies had pitched around the 19-year-old wunderkind in the weekend's first two games. Hamels went right at him. Harper responded in his own way.

He went from first to third on a Werth single to left. With a 1-2 count to Chad Tracy, Hamels tossed to first to keep Werth close. Harper danced down the line, but retreated to third. Hamels checked Werth again, and this time, Harper dashed toward the plate. Laynce Nix's throw was high and Harper slid under Carlos Ruiz's tag.

He bounced up, yelled into the night, and high-fived Tracy. Then he shot a two-second look at Hamels before stepping into the dugout, where his manager, Davey Johnson, greeted him with a wide smile. Harper was the first major-league teenager to steal home in 48 years. The rivalry was born.

If taking an early lead wasn't enough retaliation, Nationals starter Jordan Zimmermann plunked Hamels on the left shin as he attempted a third-inning bunt. Immediately, home-plate umpire Andy Fletcher warned both benches. The beanball stopped, but feelings were made clear.

"They can say whatever they want," Hamels said.

That's when the Phillies grabbed control. Pence turned on an inside Zimmermann fastball and deposited deep into the left-center bleachers for a two-run bomb. Polanco, dropped to seventh in Charlie Manuel's 24th different lineup in 29 games, delivered another run with a single up the middle to score Nix.

They scored six more in the ninth to guarantee victory and make Hamels' complete-game bid superfluous. He had done plenty enough, and it started with a fastball that intentionally struck baseball's next star.

Contact Matt Gelb at mgelb@phillynews.com or follow on Twitter @magelb.