Delaware Senate candidate Chris CoonsChris CoonsDem blasts Trump on 'jail' line: 'That's what dictators do' Election-year politics: Senate Dems shun GOP vulnerables Overnight Healthcare: McConnell unveils new Zika package | Manchin defends daughter on EpiPens | Bill includes M for opioid crisis MORE (D) said Republican Christine O'Donnell's victory in the GOP primary was "positive" for his campaign.
"Obviously, I went from being significantly down to significantly up in the polls, so just from an outside-in view, it's a positive in terms of my chances in the election," he told ABC's Christiane Amanpour in an interview that aired on "This Week."
"But I don't think it's been positive for Delaware," he said. "There's been a huge amount of attention paid to things that aren't directly connected to what matters to Delaware."
Rep. Mike Castle (R-Del.), whom O’Donnell defeated in the primary, would have been a stronger opponent, Coons said.
"Congressman Castle, absolutely. He's got experience. He's got years of insight. He was a two-term governor, and he's got the experience that comes from knowing how to make hard decisions and then their consequences," he said.
Coons noted that O’Donnell had made several runs for the Senate, including against then-Sen. Joe BidenJoe BidenAmerica’s Eastern European mess Huckabee to Biden: Trump can land a 'face kick' The Trail 2016: Election night cliffhanger MORE in 2008.
"She's run for the — for the United States Senate three times in five years. That's a lot of persistence," Coons said. "I think my grandmother would have said she has a lot of moxie. … I'm not sure why she's running, but that's up for — that's up to her to explain."
Coons said he's aware of how important Delaware in helping Democrats keep control of the Senate.
"I don't think there's a scenario where the Republican take control of the United States Senate if I'm successful in this Senate seat," Coons said. "And I've been told that's a critical strategic concern for folks who are looking at this race from outside."
O’Donnell, meanwhile, reiterated her complaint that national and Delaware Republicans aren't helping her campaign.
"The state party isn't helping us," she said. "And we're asking the national Republican senatorial to help us. We've got the Democratic senatorial committee coming after me. We're hoping that the National Republican Senatorial Committee will help us. But it's two-and-a-half weeks left, and they're not."