ROXBURY – Shaleyse Smallwood proudly remembers winning the Boston City League championship with the O’Bryant girls basketball team as a senior in 2004.

Twenty-one years later, she felt that same pride in accomplishing the feat with her alma mater as head coach.

Behind an unstoppable 19 points and 22 rebounds from junior Melissa Cuevas, and an all-around defensive performance to lock down late, the Tigers (17-2) outlasted a resilient Snowden team, 51-39, Thursday night at Madison Park for their first BCL championship since 2013.

The loss marked the first of the year for the Cougars (19-1) and head coach Phibe Pham, who is married to Smallwood. Meanwhile, O’Bryant avenged a loss in the final last year.

“It feels great,” Smallwood said. “It’s been a long time coming. There’s something special building here. This is my alma mater. I came here seven years ago, I won my senior year. To come back and win it (is great).”

“We all have a strong bond,” Cuevas added. “Last year, we made runner-up and we lost to New Mission. But this year, our main goal was just winning city championship.”

Much of the first three quarters were tight, as teams utilized their strengths well to trade runs.

Cuevas dominated the paint and the Tigers collected 29 offensive rebounds to start pulling away several times, building a nine-point lead in the second quarter and a six-point lead in the third. But Snowden freshman Jenalis Mercado won tournament MVP in the loss with 27 points, erupting for 21 of them in the first half to keep the Cougars in it.

Many of those points came on the fast break, with Mercado (four steals), Elida Vicente (eight points, three steals) and Synnae Fitzpatrick (four points, three steals) generating a slew of turnovers to find Mercado in open space. And even as O’Bryant limited Mercado in the third quarter, Vicente took over the scoring load to trail just 38-35 entering the fourth quarter.

But Cougars turnovers spiked and the second-chance scoring kept coming for the Tigers to outscore them 13-4 the rest of the way.

“Our defense (was the difference),” Smallwood said. “It was able to get some turnovers. … We’ve been hanging our hat on our defense all year.”

Julia Manning (six points, four steals, five rebounds), Nia Buyu (eight points, five rebounds, three steals) and Amira Mohamed (seven points, four rebounds, two steals) each played vital roles for the Tigers, especially on defense.

Cuevas just couldn’t be stopped, standing out with 16 offensive rebounds.

“That’s been her all year,” Smallwood said. “I tell her all the time she’s our biggest (player) down there. So she has to get down low, get rebounds, and she did that for us today.”