(CNN) -- Sen. Barack Obama decisively defeated Sen. Hillary Clinton in North Carolina Tuesday, but Clinton's narrow victory in Indiana will likely send the race for the Democratic presidential nomination on to the next round of primaries.
Sen. Barack Obama and his wife, Michelle, greet supporters in Raleigh, North Carolina.
As polls closed in Indiana, Clinton had a double-digit lead over Obama, but by the end of the evening, Clinton's lead had shrunk, dragging the race out until early Wednesday.
A clear winner did not emerge until 1:15 a.m. Wednesday -- seven hours after the polls closed -- because results were slow to come in from Lake County, a Chicago suburb in northwestern Indiana with several precincts that went strongly for Obama.
By Wednesday morning, all absentee ballots had been counted in Lake County and the final results showed Obama had taken the county by 12 percentage points.
There were 115 delegates at stake in North Carolina and 72 in Indiana.
Because Democratic delegates are awarded proportionally, Obama added four delegates to his lead, according to CNN estimates.
Obama earlier claimed a decisive victory in North Carolina.
"Some were saying that North Carolina would be a game-changer in this election. But today, what North Carolina decided is that the only game that needs changing is the one in Washington," Obama told supporters in Raleigh, North Carolina. Watch Obama thank his supporters »
Obama took an overwhelming 91 percent of the black vote in North Carolina, according to exit polls, while Clinton claimed only 6 percent.
Clinton took 59 percent of the white vote compared to 36 percent for Obama, according to the polls.
Clinton told her supporters in Indianapolis, "it's full-speed on to the White House." Watch Clinton greet her supporters »
Clinton made a strong pitch to blue-collar workers in Indiana. She pulled a majority of the votes in rural and suburban Indiana during Tuesday's primary.
In CNN exit polling, Clinton took 53 percent of the vote in suburban areas, compared with 47 percent for Obama of Illinois. She took 68 percent of the rural vote compared with Obama's 32 percent.
In all, 1,738 voters were polled.
Clinton had pitched herself as the candidate best-suited to turn around a flailing economy and consciously courted working-class voters in the state -- even driving a pickup truck up to a gas pump once to help promote her proposed temporary rollback of federal tax on gasoline.
"I believe that Americans need a champion in their corners," she said at a rally in Indianapolis. "For too long we've had a president who has stood up and spoken out for the wealthy and the well-connected, but I don't think that's what Americans need.
"Standing up for working people is about the American dream and about the Democratic Party; standing up for the middle class is who we are and what we can be if we stick together."
Eighty-nine percent of Indiana voters said they have been affected by what they called a recession. Clinton had a slight edge when voters were asked who is most likely to improve the economy -- taking 49 percent to Obama's 47 percent.
The candidates now turn their attention to the upcoming contests in West Virginia, Kentucky and Oregon.
According to early exit polls, half of Clinton's supporters in Indiana would not vote for Obama in a general election matchup with Sen. John McCain, the presumptive Republican presidential nominee. Watch what the exit polls show »
A third of Clinton voters said they would pick McCain over Obama, while 17 percent said they would not vote at all. Forty-eight percent of Clinton supporters said they would back Obama in November.
Obama got even less support from Clinton backers in North Carolina, where 45 percent of Clinton supporters said they would vote for him over McCain. Thirty-eight percent of Clinton supporters said they would vote for McCain while 12 percent said they would not vote.
Obama voters appear to be more willing to support Clinton in November. In Indiana, 59 percent of Obama backers said they'd vote for Clinton, and 70 percent of Obama backers in North Carolina said vote for her against McCain.
Obama on Tuesday said he didn't agree with those who said his party would not be able to unite.
"Tonight, many of the pundits have suggested that this party is inalterably divided -- that Sen. Clinton's supporters will not support me, and that my supporters will not support her," he said.
"I'm here tonight to tell you that I don't believe it. Yes, there have been bruised feelings on both sides. Yes, each side desperately wants their candidate to win. But ultimately, this race is not about Hillary Clinton or Barack Obama or John McCain.
"This election is about you -- the American people -- and whether we will have a president and a party that can lead us toward a brighter future."
Obama currently leads in pledged delegates and in states won, and he is ahead in the popular vote, if Florida and Michigan are not factored into the equation. Those states are being penalized for moving their primaries up in violation of party rules.
With neither candidate expected to win the 2,025 delegates needed to clinch the Democratic nomination by June 3, the end of the primary season, the final decision will most likely fall to the 796 superdelegates: Democratic governors, members of Congress and party officials. Watch how superdelegates could come into play »
Both candidates have spent the past two weeks shuttling between Indiana and North Carolina, each arguing to crucial working-class voters that their rival is out of touch when it comes to the pocketbook issues that are dominating the campaign.
CNN's Susan Candiotti, Dan Lothian and Paul Steinhauser contributed to this report.
All About U.S. Presidential Election