In conceding defeat, Lugar slammed Murdock — and the rest of the Republican Party in Washington — for being too partisan.
"If Mr. Mourdock is elected, I want him to be a good Senator. But that will require him to revise his stated goal of bringing more partisanship to Washington," he said in a lengthy statement released after the results were clear.
"He and I share many positions, but his embrace of an unrelenting partisan mindset is irreconcilable with my philosophy of governance and my experience of what brings results for Hoosiers in the Senate," Lugar added.
Donnelly also argued in his post-election statement that Mourdock was politically extreme.
"Mourdock once said he 'didn’t take a pledge that [he] would support every job in Indiana,' " Donnelly said in his statement. "I wholeheartedly disagree. While Richard Mourdock trumpets his Tea Party ideas and claims bipartisanship is a dirty word, I will be meeting with the hardworking men and women of this state talking about how we can get Hoosiers back to work."
For his part, Mourdock staunchly opposed the bailout that was given to Chrysler as Indiana state treasurer, calling it "unprecedented in all of American history" in a campaign video displayed prominently on his website.
"To be a secured creditor meant that you were first in line in the event of a bankruptcy. American bankruptcy had stood for 150 years in that regard, until the Obama administration decided they didn't like that and they changed the rules," he says in the video.
Mourdock argues in the video that the money that was given to Chrysler was "looted" by the federal government from the pension funds of Indiana retirees who had been public employees.
"It was unconstitutional and illegal. I kept waiting for someone to take the lead to take on the federal government," he said. "When no one did, I stepped forward."
In an interview with CNN Wednesday, Mourdock made no apologizes for his stance on the auto bailouts.
"You never compromise on principles — if people on the far left have a principle they want to stand by, they should never compromise," he said. "Those of us on the right should not either."