State Rep. Geoff Diehl will face U.S. Sen. Elizabeth Warren in November, in a sneak preview of the much-predicted Warren-Trump contest of 2020.
Diehl took the three-way GOP primary over Beth Lindstrom of Groton and John Kingston on Tuesday.
Unofficial results place Geoff Diehl with 143,735, or 55 percent. Kingston finished second with 69,429 votes, or 27 percent, with Lindstrom third with 46,614, or 18 percent.
Warren said in a release she has accepted three debates with Diehl, two in October and another yet to be set.
Diehl's camp said it has accepted Warren's challenge.
Warren called on her GOP rival to stick to the issues.
"We've accepted three general-election debates because Massachusetts voters deserve serious policy conversations as the balance of the Senate is on the line," she said.
Diehl thanked his supporters and then questioned Warren's commitment to the Bay State.
"Thank you to the people of Massachusetts that made tonight possible," Diehl said to a raucous crowd in his hometown of Whitman. "We made history today. ... This is our victory. This is our moment."
Diehl said Warren is more interested in running for president in 2020 than helping at home.
"She's not interested in Massachusetts," he said. "You know it. She's looked right past us and the issues we care about. We clearly cannot depend on her when her focus is always on her political future.