WASHINGTON (CNN) -

The U.S. Chamber of Commerce is ramping up efforts on behalf of North Carolina Republican Senate nominee Thom Tillis in one of the most watched and most expensive Senate races this election year.

The Chamber on Wednesday is launching its second general election ad boosting Tillis and also going after the freshman Democratic incumbent by tying her to President Obama.

"Kay Hagan and the Obama administration have it backwards: record spending, record debt, a stagnant economy," says the ad.?

Chamber officials would not say what they paid for the two-week buy but called the amount "significant."

The spot does not mention that Tillis is the state's House speaker. His tenure has been controversial because of a budget passed that critics said hurt public education. Tillis has disputed that.

The ad calls him a "conservative businessman" and "an independent voice who led North Carolina's balanced budget effort."

The ad comes on the same day the two candidates face off in their first debate. Polls have shown the race neck and neck.

During the debate, Hagan is expected to face more questions about her views on Obama. Last week, as the President came to North Carolina to address the American Legion, she said the administration had not done enough to help veterans.

The GOP needs six seats to take control of the Senate, and Hagan's is one of the Republicans' and their allies' top hopes.

Democrats, knowing a North Carolina win in November is key to helping them keep the majority, are fighting back. The Democratic Senatorial Campaign Committee launched a $9.1 million ad campaign in August attacking Tillis.

The huge influx of outside money from groups on both sides has led to nearly $30 million spent on the race so far, according to the Center for Responsive Politics.