Allison Cartwright won the Democratic nomination to be the next Supreme Judicial Court Clerk for Suffolk County, defeating Boston City Councillor Erin Murphy in a state primary election on Tuesday that featured few competitive races and just a trickle of voters.

Cartwright was the clear winner in Boston by a 60-40 margin, according to preliminary results from the city’s Election Department, and her lead was called “insurmountable” by allies who gathered in Jamaica Plain to celebrate her victory.

Later, updated city election results showed that Cartwright dominated the race in Boston, winning 18 of the city's 22 wards, including those that encompass Dorchester and Mattapan. Murphy won ward 16 in the Neponset section of Dorchester and in Charlestown and South Boston. By precinct, Cartwright won Boston by a tally of 216-55.

The race for the administrative seat, which has been held by Dorchester’s Maura Doyle for nearly three decades, attracted outsized attention in part, because Murphy—a sitting Boston city councillor— would have moved on from her at-large council seat to take the SJC role.

The contest also took on the dynamics of a proxy battle between political rivals, with Mayor Wu and other prominent progressives pushing hard for Cartwright, an attorney who touted her deep experience in the field, while Murphy drew support mostly from Wu critics and centrist allies.

Several local elected positions featured Democrat incumbents with no opposition in their primary elections this year, including Congresswoman Ayanna Pressley, Congressman Stephen Lynch, state Sen. Liz Miranda, state Reps. Brandy Fluker Oakley, Chris Worrell, and Dan Hunt.

State Sen. Nick Collins handily defeated opponent Juwan Skeens, while State Rep. Russell Holmes won decisively over his two opponents: Haris Hardaway and Samuel Pierce.

The general election — featuring the presidential contest— will be held on Tuesday, Nov. 5.