St. Stephen’s/St. Agnes Coach Kathy Jenkins, shown here in 2009, is nearing 600 career victories at the Alexandria school. (John McDonnell/THE WASHINGTON POST)

In the beginning, Kathy Jenkins could only lean on what she knew, and so early St. Agnes girls’ lacrosse practices had the feel of a basketball workout on grass.

Basketball fundamentals, such as man-to-man defense and off-the-ball offensive movement, seemed to fit her new sport, and so Jenkins — who co-founded the program with Alix Fellows in 1976 at what is now St. Stephen’s/St. Agnes — often ran her team through basketball drills to teach the concepts.

More than three decades later, Jenkins’s passion to teach lacrosse to local girls remains strong, and just as important in her mind, she hasn’t stopped learning along the way, either. The second-ranked Saints beat Bullis, 18-4, on Wednesday for Jenkins’s 599th career win. She can reach 600 on Thursday when the team hosts Holy Child.

“I’m constantly trying to learn what I can do better,” Jenkins, 61, said. “I don’t ever feel like I know it 100 percent. I watch the sport as much as I can because even just watching a college team go through warm-ups you can pick up something new.”

Jenkins — a two-time All-Met Coach of the Year — arrived at the then-all girls school in Alexandria as a 20-year-old with two years of college schooling and finished her degree taking classes around her first years of teaching. Although she had never played the game before, she helped launch girls’ lacrosse as part of a course at American University that required her to start a school program.

St. Stephen’s/St. Agnes has grown into an area and national power with Jenkins guiding the team to 24 conference tournament titles and eight undefeated seasons in all. The Saints (17-3, 4-1 ISL AA) had not lost an Independent School League game since 1995 before falling in overtime to top-ranked Georgetown Visitation on April 18.

The school believes the only high school girls’ lacrosse coach in the nation with more victories than Jenkins is Greenwich Academy (Conn.)’s Angela Tammaro, who is in her 47th season.

“We want to play hard for her,” said senior Paige Patterson, who had never played lacrosse before Jenkins introduced it to her in sixth grade. “She cares so much for the sport that you’d feel like you were wasting her time and yours if you gave anything less than your best.”

As she nears another milestone victory, Jenkins, who also helps with the school’s girls’ basketball and tennis programs, will try to keep the focus on her team, which has been led this season by returning All-Mets Michele Phillips and Carly Reed.

The Saints marked her 500th win in 2008 with cake and special t-shirts, and the veteran coach said she expects a similar low-key celebration this time around as the group gears up for another postseason run.

“I really just want the girls to do well for themselves,” Jenkins said. “I know how hard they work and how much they want to play well. I get the credit for putting them in the right places if they win, but they’re the ones out there having to do it.”