Democratic Rep. Chris Pappas and Republican former Sen. John E. Sununu won their respective Senate primaries Tuesday in New Hampshire, formalizing a fall matchup for an open seat that both sides have already begun fighting over.

With over 80 percent of votes counted, Pappas was leading biochemist Karishma Manzur, 65 percent to 33 percent, The Associated Press reported, while Sununu was ahead of former Massachusetts Sen. Scott P. Brown, 68 percent to about 27 percent, with close to 80 percent of the estimated vote in.

In the race for the battleground House seat Pappas is vacating, former Portsmouth City Councilor Stefany Shaheen, the daughter of retiring Democratic Sen. Jeanne Shaheen, clinched the Democratic nomination, besting a crowded primary field. With nearly 90 percent of votes counted, she was leading Marine Corps veteran Maura Sullivan 37 percent to 35 percent just before 1 a.m. Eastern time Wednesday, the AP reported.

The Senate race to succeed the senior Shaheen in New Hampshire could be crucial to deciding control of the chamber this fall, and both parties are bracing for a tight general election. Pappas has warned Democrats not to take the contest for granted, even though Republicans haven’t won a Senate race in the state since 2010.