DENVER -- Barack Obama on Tuesday won over Colorado voters whose top concern was the economy, becoming the first Democrat to carry the battleground state since 1992.

And in the U.S. Senate race, Democrat Mark Udall defeated Republican Bob Schaffer, giving both U.S. Senate seats to Democrats for the first time since the mid-1970s.

Democrats had targeted Colorado this year as part of a strategy to conquer Western states following dramatic victories across the region over the past eight years. In August, Obama accepted his party's nomination at the Democratic National Convention in Denver.

"Colorado, this is a new day. It's a new day for this nation and this world," former Gov. Roy Romer told hundreds of people at a Democratic celebration downtown.

At a Republican gathering, Schaffer said, "Colorado took a giant leap to the left this year and years prior.

"Here's what we need to keep in mind -- good campaigns don't end on Election Day. Win or lose, if the ideas matter, if the values are for real, if the vision is clear, we just keep going," he said.

With 66 percent of the projected vote counted, Obama led Republican John McCain 53-45 percent.

Unaffiliated Colorado voters leaned more toward Barack Obama than McCain, according to an Associated Press poll of voters over the past week. Obama also did well among women, moderates, Hispanics and people seeking change, but he wasn't necessarily a slam dunk among voters younger than 30. The poll showed McCain drew voters who described themselves as born-again or evangelical Christians.

Denver resident Akinye Chatmon, 31, said he hasn't voted since 1996 because he didn't like the candidates. This year, he voted for Obama and volunteered for the campaign.

"I felt like if I want to make my voice heard, instead of talking so much, I'd go vote. For the first time in 12 years," he said.

As she waited to cast her ballot, Yvonne Hobrecht of Lakewood said, "It's a very historical time, this election."

McCain fought hard for Colorado, visiting frequently as did running mate Sarah Palin. His campaign couldn't match the resources poured into Colorado by the well-funded Obama campaign.

Obama opened more than 50 offices across the state, recruiting young and old to carry the torch. Huge crowds welcomed him wherever he went, even in conservative strongholds that included Grand Junction and El Paso County.

Obama's victory was another blow to Colorado Republicans, who have lost two U.S. House seats and a U.S. Senate seat in just four years.

Colorado has voted for a Democratic presidential candidate only three times since 1948, when it went for Harry Truman. Lyndon B. Johnson won here in 1964, and Bill Clinton in 1992.