The promise uttered by Jen Narlee to Medfield High assistant coach Ellen Gelinas  was made in a fog of shock and disappointment after an unexpected overtime loss to Hopkinton in last year’s Division 2 South quarterfinals.

The gist of it, though, was that Narlee wouldn’t let the Warriors endure the same fate twice.

“I basically said ‘I’m ready to take this,’ ” Narlee explained. “ ‘I’m ready to go. I don’t want to have any regrets next year. I’m ready to put it all out on the floor.’ That was it.”

Ten months later, she is following through.

Narlee, the Tri-Valley League MVP as a sophomore two years ago, has adopted a more aggressive style as a senior, and taken her game to new heights. Averaging 11.6 points, 7.8 rebounds, 4.6 steals, and 1.7 blocks per game, the 5-foot-11 center has sparked Medfield to a 10-1 start.

“I’ve seen things out of Jen this year that I haven’t seen from her in the past three years,” said coach Mark Nickerson .

“She’s become much more of an offensive threat. She’s playing much more physical in the post, she’s using her body to gain position,’’ Nickerson said.

“She had 22 points and 14 rebounds against Coyle-Cassidy in our winter tournament, and it was the best I’ve ever seen her play. And that says a lot for a girl who was league MVP two years ago, and is going to threaten 1,000 points and 1,000 rebounds’’ for her high school career.

Narlee is a captain for the second straight season and one of three seniors on this year’s roster, along with cocaptain Ali Gold  and Katelyn ­Noschese .

Last season, without any seniors, Medfield went 22-2 and earned the No. 2 seed in the postseason tournament. Twelve of 13 players from that group returned this season, giving the Warriors instant chemistry — as well as saddling the team with high expectations.

As they did last year, the players speak openly about their hopes of winning a state championship.

“Our expectations are set pretty high because we’re a really good team, in my eyes,” Narlee said. “Last year we were really good too, but we didn’t have the experience. We were a young team, and we had no seniors. Me and Ali, we had some experience being leaders, but now we’re really up to that challenge.”

Medfield had beaten opponents this season by an average of 29.2 points through 11 games. The reigning four-time TVL champs are once again proving to be the class of the league, winning their first six games against Tri-Valley rivals by an eye-popping average of 34.5 points.

Narlee had 15 points, 10 rebounds, and 6 steals to lead her team to a 70-37 win over Westwood last week.

“They play well, they play hard, and they’re well coached,” said Shannon Clark . in her first year as Westwood’s coach. “One day, we’ll hopefully be there.”

While Narlee has held things down in the paint, junior point guard Lauren Petit  and junior small forward Kristin Fechtelkotter  have been equally effective on the perimeter.

The 6-foot Fechtelkotter leads the team in scoring with 15.2 points per game, and Nickerson says Petit may be the team’s “most important player” for her role in dictating Medfield’s pace. She averages 11.7 points, 3.5 assists, and 5.1 steals per game.

Medfield has also received solid contributions from 5-foot-10 sophomore Payton Ouimette , who has stepped into a starting role while junior forward Kate Thomas  recovers from a knee injury.

Narlee has made as significant an improvement as any of her teammates, however.

For most of her high school career, she has focused on soccer over basketball. She was a center midfielder and captain on last fall’s Division 2 state title team and a key piece on the Warriors team that won the state soccer crown in 2010.

But after feeling the sting of the playoff loss to Hopkinton, she has zeroed in more on basketball. For the first time in her high school career, Narlee is not playing indoor soccer during the winter season.

“I think the player that took that loss last year to heart the most was Jen,” Nickerson said. “There are some things she said last year that I think have motivated her to work harder, and to play a little bit harder so that we don’t have that happen again. Jen has always been a soccer-first player. That was her passion, that’s what she spent the most time on — this is a girl that didn’t play AAU basketball. But I think that changed after last season. She was extremely motivated to make up for how last year ended.”