Mourdock told the Washington publication Politico he anticipates being knocked hard by Democrats.
"They will certainly run, negative crazy TV commercials," he said. "They'll change themes. [But] we are at that time of the season, frankly, when I think people are almost tuning them out. ... I don't know if they're going to have much impact."
Mourdock cited the importance of the race as a reason Republicans will stick by him.
"This race is for the majority [of] the United States Senate," Mourdock said. "I've got a lot of ... calls of encouragement" from Republican leaders. "They recognize this race is about more than one comment in one speech, it's about 51 votes ultimately."
Mourdock, locked in a battle with Democrat Joe Donnelly and Libertarian Andrew Horning, responded to a question about abortion during a debate Tuesday, saying he believed, "Life is that gift from God. I think that even when life begins in that horrible situation of rape, that it is something God intended to happen," The Indianapolis Star reported Wednesday.
His comments drew immediate reaction on online social media, with some posters saying his remarks should disqualify him from the Senate race, the Star said.
Mitt Romney distanced himself from the Indiana Republican, with the Republican presidential candidate's spokeswoman saying, "Gov. Romney disagrees with Richard Mourdock's comments, and they do not reflect his views."
President Obama's campaign said Mourdock's remarks reflected "a GOP that is way out of mainstream" and Mourdock's remarks were "outrageous and demeaning to women."
Obama campaign spokeswoman Jen Psaki said women will be concerned about what it could mean if Republicans take control of the Senate and White House.
"If [Republicans] have the opportunity to be partners, in the White House and the Senate, then that is something that women should have, and I think will have, concern about as they are going to the voting booth," Psaki said.
Mourdock later tried to clarify his comments, saying it was "sick" and "bizarre" that anyone would conclude he was saying God had intended the rape, the Star said.
"What I said is God creates life. As a person of faith I believe that," he said. "Does God want people raped? Of course not."
Mourdock, who ousted longtime Sen. Richard Lugar in Indiana's GOP primary, is running an ad on Indiana television in which Romney endorses him, Politico reported.
Democrats have criticized the Mourdock comments and have linked them to the "legitimate rape" comments from U.S. Rep. Todd Akin, a Missouri Republican trying to unseat Democratic U.S. Sen. Claire McCaskill. Akin's campaign was dealt a blow in August when he said rape victims have a biological ability to avoid pregnancy.