Donald Trump’s campaign manager acknowledged Thursday that Mr. Trump is trailing Hillary Clinton in the polls, but said that “helps light a fire under us” and that Mrs. Clinton’s fundamentals are still weak.

“I think it helps us to be a little bit behind, and we are,” Trump campaign manager Kellyanne Conway said on CNN’s “New Day.” “It helps light a fire under us, and it reminds us of what we need to do to get this done.”

Ms. Conway said the topline “horse race” numbers look good for Mrs. Clinton, but that the Democratic presidential nominee’s fundamentals still aren’t great if one looks more closely at the cross tabs.

“It’s not as if a majority of Americans now say I like her or I much trust her,” she said.

Ms. Conway said Mr. Trump has lost some votes among Republicans - and said those aren’t people who are going to go to Mrs. Clinton.

“They’re basically saying I don’t like the way the last couple weeks went, and I want you to get back to fighting Hillary Clinton,” she said.

In a somewhat awkward exchange on CNN Wednesday, Michael Cohen, an executive at the Trump Organization, repeatedly asked “says who?” when it was pointed out that Mr. Trump is trailing in the polls.

Mrs. Clinton leads Mr. Trump head-to-head by about 6 points in the latest national Real Clear Politics average, though the margins vary from 1 point to 9 points.

Ms. Conway, a GOP pollster herself, said they’re going to take the issue of Obamacare to women, who she called the “chief health care officers” of their households.

She also said she talks to a lot of “security moms” as well as “security non-moms.”

“I’m very focused on non-moms, which is a growing group in our country — people who choose not to be married and choose not to have children,” she said. “They’re very concerned about security — economic security, health security, and certainly national security.”

Ms. Conway also said the upcoming presidential debates will be “incredibly important” in moving the poll numbers and that debate prep is going to start this weekend.

She said she thinks Mr. Trump will be very happy with the choice of who will play Mrs. Clinton in debate prep, but declined to provide the name.

She said former Fox News chairman Roger Ailes and Mr. Trump have been friends for “decades,” but said Mr. Ailes doesn’t have a formal position in debate prep to her knowledge.

Asked if Mr. Ailes is helping with debate prep informally, Ms. Conway said: “They’re friends, and he talks to many people.”

“He talks to many people when we’re not around, so it’s not for me to say,” she said.

“But I will tell you — people would be surprised at who and how many folks truly want to help and I have not heard many people of late say ‘we just have to stop Hillary; I don’t want Hillary.’ They’re excited about Donald Trump’s candidacy,” she said.