Donnelly's win dealt a blow to the tea party, which had hoped to snag one of its biggest campaign prizes with a Mourdock victory. Nonetheless, the stage is set for a conservative Statehouse that could continue the policies started under Daniels.
"At least there will be some continuity," said Harry Gaunt, an 81-year-old ex-Marine and Indianapolis jeweler who voted for Pence.
Republicans also made gains in Indiana's U.S. House delegation and the General Assembly, but several Statehouse races were too close to call Tuesday, and it was unclear whether the GOP would have a supermajority in the House.
In another Democratic upset, Glenda Ritz beat Republican state school Superintendent Tony Bennett, whom teachers had opposed because of sweeping changes he has pushed in the state's schools.
In the Republican primary in May, Mourdock knocked off Lugar, a six-term Senator, but he couldn't translate that win into a general election victory, especially after his comments during an Oct. 23 debate that a pregnancy resulting from rape is "something God intended."
Donnelly, a three-term Democratic congressman from northern Indiana, drew support from Lugar backers and Mourdock opponents. With most precincts reporting, Donnelly collected 50 percent of the vote to Mourdock's 44 percent.
Janet Sutton, of Indianapolis, said she voted for Lugar in the primary and Donnelly on Tuesday, even though she wanted Republicans to win a majority in the Senate.
"I sat in there quite a while trying to figure out which way I was going to go," said Sutton, who is in her 60s. "I did not like some of the issues Mourdock had."
Kathy Weddle, 42, of Osceola in northern Indiana, also voted for Donnelly.
"That's just a stupid comment," she said of Mourdock's debate statement. "God would not want that to happen. Being someone who took a long time to get pregnant, I don't believe God makes (a) decision on that."
Romney's win in Indiana was founded on support from whites, conservatives, voters older than 40 and people with family incomes of at least $50,000. Obama, who in 2008 gave Democrats their first Indiana presidential ticket victory since 1964, lost ground with younger people and those with incomes of more than $100,000.
Republicans picked up one seat in the state's congressional delegation, with former state Rep. Jackie Walorski's victory over Brendan Mullen in the 2nd District. All of the state's congressional incumbents won re-election, and Republicans Susan Brooks and Luke Messer picked up open seats in the 5th and 6th Districts, respectively.
After winning the state schools post, Ritz said parents, as well as teachers, disliked Bennett's agenda, which she saw as more political than educational.
Voting was heavy across the state but went smoothly for the most part, said Valerie Kroeger, a spokeswoman for the Indiana secretary of state's office.
There were a few wrinkles, however. A bank robbery and shootout in Muncie made it difficult for voters to get to one polling site, and election officials in Bloomington said a misleading email caused confusion over where Indiana University students were supposed to vote.
Significant voting delays were reported in heavily Republican Hamilton County just north of Indianapolis, where voters were still standing in line at some sites an hour after the deadline for polls to close passed. Officials there said the lines were due more to voter turnout than to a technical glitch that delayed the start of voting at some sites.