What are the biggest differences between identical twins Jacob and Xavier Kahn?

Dyed hair, 10 pounds, one minute and 0.21 percent of their GPAs.

Jacob and Xavier were named this year’s valedictorian and salutatorian, respectively, of Greenport High School, with just two-tenths of a difference between their unweighted averages. According to Principal Gary Kalish, this is the first time in Greenport’s history that the top two students are siblings.

The 17-year-olds say they have always been competitive in everything they do — academics, sports, even games they made up in their front yard.

“We would always beat each other with sticks down our driveway,” said Xavier with a laugh. He’s one minute older than his brother and dyed his hair blonde as part of a varsity tennis team tradition. (Jacob is on the team as well, but decided to stick with his natural roots this year.)

“I remember the rule was you’re just supposed to hit the stick, you’re not supposed to hit the person,” Jacob explained.

Xavier added, “But if you accidentally hit their hand …”

“It really got us going,” Jacob said.

On the tennis court, the brothers tried to outdo each other throughout high school.

“Tennis was very competitive since you compete for positions on the court,” Jacob said. “Xavier was always better since the beginning … Sometimes I’d beat him and get first, but then I quickly got beat back down to second.”

But during their senior year, the brothers realized that in order to win, they had to team up. They played doubles all year and ultimately became the Suffolk County Division IV doubles champions.

“Instead of being so focused on beating each other, I would say, it was more focused on just not messing up,” Jacob said.

Along with the tennis team (of which Xavier is captain), the twins play varsity soccer (with Jacob as captain) and performed in school musicals together. Jacob is president of the student council and Xavier is president of the senior class. Throughout high school, they both excelled in academics and pushed each other to be better.

“If I saw his paper and it was 100 and mine was 98, I was like, ‘Oh, I stink,’” Xavier said.

The brothers said they weren’t surprised to earn the top spots in their graduating class. Jacob is headed to the United States Air Force Academy in Colorado Springs, Colorado, and Xavier will attend Vanderbilt University in Nashville, Tennessee. For now, they both plan to study engineering, but Xavier is considering a switch to a language major.

Greenport’s graduating class of 53 students will accept their diplomas on June 23. Jacob and Xavier said they haven’t written their speeches yet for the ceremony, but perhaps they’ll stick with what they know — they both wrote their college essays about being twins.

“I wrote about our competitive nature, and how it prepared me,” Jacob said.

Said Xavier, “It probably made us into who we are.”