Regional high school graduates and doubles partners Kat Roberts and Lizzie Williamson solidified their place as the best high school doubles team in Massachusetts after defeating Newton South in the state doubles championship in Shrewsbury over the weekend.

The victory marks the third straight doubles championship for Williamson and the first for Roberts. Williamson won her first two with the help of partner junior Victoria Scott, who was in the crowd at the final cheering them on.

Coach Liz Roberts, who is also Kat’s mother, said the two were down early on by two games on the hot day. It didn’t last long. They quickly shook off the nerves, winning the first set 6-4 before a second set that they won decisively 6-0.

At the trophy ceremony, teammates and Ms. Roberts looked proudly on at the pair who are also best friends.

“It was special that they played together their senior year,” said Ms. Roberts. “It was thrilling to be there.”

Roberts and Williamson will play the last doubles match of their high school careers at the division two state team championship at Newton South High School Tuesday afternoon. The Vineyarders will play against first-seeded Winchester at 3:30 p.m.