(CNN) - In a key pick-up of a Republican Senate seat, Massachusetts Democrat Elizabeth Warren defeated GOP Sen. Scott Brown Tuesday, according to a CNN projection. With 37 percent of the estimated vote counted, Warren led Brown 52 percent to 48 percent.
The victory is critical to Democratic ambitions to maintain their majority control of the Senate.
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Warren, a Harvard University law professor and former Obama administration financial consumer advocate, beat the freshman senator who was seeking a full term to the seat he won two years after the death of Democratic Senator Ted Kennedy. Brown, the first GOP senator from deep blue Massachusetts in decades, billed himself as an independent who voted for the needs of Massachusetts not the demands of either party.
The Warren-Brown race was one of the costliest and nastiest campaigns this cycle. It was marked by Brown's repeated accusations that Warren claimed to be a minority in order to advance her career. She denied that was her motive for listing her ancestry as Native American saying she was told about her heritage by her family.