Republican Terri Lynn Land added $1.66 million to her campaign account for Michigan's open-seat Senate race in the last three months of 2013, the latest sign she'll be very well-funded for her run against Rep. Gary PetersGary Charles PetersOvernight Finance: Senate rejects Trump immigration plan | U.S. Bancorp to pay 0M in fines for lacking money laundering protections | Cryptocurrency market overcharges users | Prudential fights to loosen oversight Senators introduce bill to help businesses with trade complaints Trump spars with GOP lawmakers on steel tariffs MORE (D-Mich.).

Land raised $1 million for the quarter and added $600,000 from her own pocket. The former Michigan secretary of state has committed to spending $5 million of her own money on the race, making her instantly competitive on the cash front. 

"Terri's continued fundraising strength is proof that folks in Michigan are looking to her as a mother, small business owner and proven problem solver who will put Washington to work for the people like she did as secretary of state," said Land spokeswoman Heather Swift.

Peters has yet to announce his fourth-quarter fundraising totals. He's been averaging around $1 million per quarter in the past and had approximately $2.5 million in the bank as of the end of September, the last reporting period.

Republicans believe Land could give Peters a tough run and, if the national environment is bad for Democrats next fall, the race for Sen. Carl Levin's (D-Mich.) seat could be one of the first Democratic-leaning races to move into the tossup category.