Maura Healey

Kevin Hayden

Nick Collins

Incumbent U.S. Sen. Edward Markey held on to his seat in Tuesday’s primary, with rival Seth Moulton lagging far behind shortly after the 8 p.m. poll closing.

The Associated Press proclaimed Markey’s victory at 8:31 with 4% of the votes counted; Markey having captured nearly 75% of the ballots.

In the November election, Markey and Republican John Deaton will vie for the Senate seat that the incumbent has held since 2013.

The Markey/Moulton primary fight became something of a referendum on age as well as length of service. Moulton highlighted Markey’s age and pressed the call for younger voices in the Senate.

Among the three Democratic contenders in the Suffolk District Attorney race, incumbent Kevin Hayden bested opponents Linda Champion and Rachael Rollins.

Gov. Maura Healey, who was unopposed, will run against Republican Mike Minogue in November. Minogue beat Brian Shortsleeve, a former MBTA administrator, in the primary.

State Sen. Nick Collins garnered enough votes to head to the November election as the incumbent.