WASHINGTON — Hillary Clinton should savor the moment before she has to face the reality of time running out on her once-invincible campaign.

Her win Tuesday in the important swing state of Pennsylvania was hard-fought and decisive. Barack Obama's well-funded effort to shut her down did not come close to an upset.

But despite her victory, the dynamics of the race are the same as they've been for more than two months. Obama remains the front-runner, and that gets more important the closer the campaign comes to the end of the primary season.

"He's content to essentially run out the clock with his narrow lead, while she needs something dramatic to happen," said California-based Democratic consultant Dan Newman. "A one-run advantage in the first inning isn't a big deal, but a one-run lead in the ninth looms large."

Clinton now faces a dwindling number of contests, and she's at a steep financial disadvantage.

Obama already is spending twice as much on ads airing in North Carolina and Indiana, the two states that come up next, with primaries on May 6. He's even advertising in Oregon, a state that he should win, where voting by mail begins in the first week of May.

Obama can afford to shower every contest with campaign dollars from the $42 million he had at the beginning of April, while Clinton is in debt.

Her campaign reported that supporters responded generously to her win, with donations coming in at a faster pace than any other point in the campaign. Clinton spokesman Jay Carson said nearly $500,000 was donated in the hour after the race was called and another $300,000 in her 17-minute victory speech.

In Pennsylvania, Clinton won with the support of whites, women and older voters, according to exit polls conducted for The Associated Press and the television networks.

Underscoring the race's excitement, more than one in 10 voters Tuesday had registered with the state's Democratic party since the beginning of the year. And about six in 10 of them were voting for Obama.

Some voters had a hard time making up their minds. About a quarter of the day's voters reported having decided within the past week, and about six in 10 of them backed Clinton.

She found reason for optimism in the victory that came even though Obama outspent her 3-to-1 in the state.

"He broke every spending record in this state trying to knock us out of this race," Clinton told her cheering supporters. "Well, the people of Pennsylvania had other ideas tonight."