Martha Coakley won the Democratic primary in the Massachusetts Senate special election, putting her on track to assume the seat long held by the late Edward M. Kennedy (D) and become the state’s first woman Senator.

Coakley, the popular state attorney general, will face state Sen. Scott Brown (R) of Wrentham, Mass., an easy winner in the Republican primary, in a special election general contest on Jan. 19.

Given the state’s strongly Democratic tilt, she is heavily favored to prevail in that matchup and continue the state’s tradition of sending strong progressives to Congress.

Coakley led from start to finish in the four-person Democratic field, comfortably defeating her nearest rival, Rep. Mike Capuano, 47 percent to 28 percent with 98 percent of precincts reporting. Community service advocate Alan Khazei and investor Stephen Pagliuca were locked in a tight race for third, at 13 and 12 percent, respectively.

Brown defeated businessman Jack E. Robinson in the GOP contest, 89 percent to 11 percent.

The special election was triggered by Kennedy’s death Aug. 25 from brain cancer. The Senate’s “liberal lion— had held the seat for more than four decades. Sen. Paul Kirk (D) was appointed in September to fill Kennedy’s seat on an interim basis, but he did not run to fill the rest of his term, per stipulations that came with the appointment.

With little intrigue or conflict, the contest failed to generate much attention across the state. The vote count was on track to be less than 1 million across both parties, out of more than 4 million registered voters. It will, however, surpass estimates made by the Massachusetts secretary of state’s office that as few as 300,000 to 500,000 people could vote.

The Democratic race in particular did not live up to early expectations for a barnburner, given the rarity of a Senate opening and the number of ambitious Democrats expressing interest. Several prominent Democrats passed up a run, including Kennedy’s nephew, former Rep. Joe Kennedy, winnowing the field to four. Two of those running — Pagliuca and Khazei — had never before run for office. Coakley, the only statewide officeholder in the field, established an early lead in the polls that she never relinquished and was the favorite going into Election Day thanks to a broad-based coalition of supporters and strong favorability rating across the state.

Despite gaining momentum in the final weeks of the campaign, Capuano was unable to close the gap. Known as a fiery liberal in Congress, the six-term Member and former mayor of Somerville, Mass., performed well in his home base — Boston and its northern suburbs of Cambridge and Somerville — but Coakley dominated in the rest of the state.

Khazei, co-founder of the City Year volunteer program, and Pagliuca, the wealthy managing director of Bain Capital and co-owner of the Boston Celtics, had both hoped to fashion upset bids as political outsiders, but neither Khazei’s grass-roots operation nor Pagliuca’s self-funding — he spent millions of his own money to blanket the airwaves with ads — proved successful.

However, political observers say Khazei proved himself a promising candidate for elected office in the future.