By Laura Trevelyan
BBC News, New York
At 1800 Eastern Time (2300 GMT), the mood at Hillary Clinton's camp in New York was cautious, with her advisers downplaying expectations, talking of a tightening race and a mixed night.
By 2130, the atmosphere had relaxed considerably, with the crowd onstage cheering wildly after victories for Mrs Clinton in Tennessee, Oklahoma, Arkansas - her adopted home state - New Jersey, Missouri and, of course, New York, her backyard.
"Madam President" read one banner.
The win over Barack Obama in Massachusetts was savoured by her supporters, as local Senator Ted Kennedy's endorsement of Hillary's rival had been seen as significant.
Evoking the memory of John F Kennedy and comparing him to Barack Obama was not as powerful as the Clinton camp had feared.
The win in Tennessee was also hailed as important by key Clinton advisers. She concentrated on the economy there, and that's what the voters wanted, said strategists.
A pattern is emerging, with Hillary Clinton leading her rival by between 16% and 18% in the states where she is victorious.
So far so good - but the key prize of the night remains California, where polls close latest.
'Yes she can'
This race is like a game of three-dimensional chess, Clinton campaign spokesman Doug Hattaway told me, with many complexities.
Hillary Clinton said the results showed the voices of "working America"
Already the focus is on the super delegates, says Mr Hattaway - the congressmen, senators, governors and Democratic National Committee members, who make up 20% of the total.
They are not bound by the results of primaries and caucuses, when they decide who to support for the nomination, and in a really tight race, with no clear victor at the end of the primaries, their voice could be decisive.
Conventional wisdom says they are the great and good of the Democratic Party, who will support Hillary Clinton and her husband.
The campaign music is getting louder, the crowd more excitable.
As Candy Crowley, political correspondent for CNN, broadcasts live from here, she is shown on the giant screen behind the stage and the crowd starts to chant: "Yes she can!"
'Purty good night'
She's number one, chanted the crowd, then the announcer boomed out, ladies and gentlemen, the next President of the United States.
Dressed in eye-catching yellow, Hillary Clinton told supporters: "Tonight we're hearing the voices of people across America."
A "purty good night", Mr Hattaway told me afterwards.
"The voters defied the pundits' expectations again, we're excited about beating the perceived momentum that Obama had," he said.
The key battlegrounds now are Maine, Nebraska and Wisconsin, he added.
The campaign music was deafening, American heartland favourites like Springsteen's Born to Run, underlining the Clinton camp's claim to represent "working America".