RALEIGH, N.C. — North Carolina Republican Sen. Thom Tillis has entered the home stretch of his competitive and costly re-election bid with nearly $2.4 million more cash on hand than Democratic challenger Cal Cunningham, according to campaign finance reports filed with the Federal Elections Commission on Thursday.

But in the period from July 1 to Sept. 30, Cunningham raised far more money than Tillis, raking in more than $28.3 million. Tillis raised less than one-fourth of that, bringing in less than $6.6 million over the same period of time.

According to Advertising Analytics, a company that tracks political television ad spending, North Carolina's Senate contest this year is the most expensive Senate race ever, with more than $242 million spent on ads. According to Kantar Media, the campaigns and outside groups have flooded the broadcast airwaves with tens of millions of dollars dedicated to reaching voters in the Raleigh and Charlotte areas.

The flurry of donations and spending comes as Democrats hope a Cunningham win will prompt the GOP to lose its Senate majority — a majority that has been used to reshape the courts, including the confirmation of two Supreme Court justices and a likely third under President Donald Trump.

A New York Times/Siena College poll of likely North Carolina voters showed Cunningham and Tillis in a close race. Cunningham's 4-point lead was within the margin of error of 4.5 percentage points. Of the 627 people surveyed between Oct. 9 and Oct. 13, Cunningham got 41% support, Tillis got 37% support and 15% were undecided.

The race was shaken up earlier this month after Cunningham confirmed on Oct. 2 that he sent romantic messages to Arlene Guzman Todd, a public relations strategist. The California woman told The Associated Press she had an intimate encounter this summer with Cunningham, who is married and has two teenage kids.

In text messages to her friend, Guzman Todd said she was physically intimate with Cunningham in his Raleigh home in July. Shortly after the revelations, the U.S. Army confirmed it opened an investigation into the matter.

During an Oct. 9 news conference conducted virtually, Cunningham on four occasions declined to answer reporter questions about whether other affairs could surface.

Hours before Cunningham confirmed he sent romantic text messages to Guzman Todd, Tillis announced he had tested positive for the coronavirus.

Cunningham has committed to remaining in the race and is hoping voters will see past his personal life, while Tillis is aligning himself closely with Trump and pushing for the confirmation of the president's Supreme Court nominee, Judge Amy Coney Barrett.