The Brookline girls had a dominant start at Wednesday’s MIAA Division 1 indoor track & field championships at the Reggie Lewis Center, winning the 55-meter hurdles, the 55-meter dash, 1,000 meters, and long jump. But entering the final event of the evening, the 4x400 meters relay, the Warriors trailed Lexington by .12 points.

The mind-set for the last race of the day was simple.

“Don’t lose to Lexington,’’ junior Sonja Nagle said. “That’s about it.’’

For the entirety of the race, Brookline and Lexington were neck and neck. One moment, Lexington led the Warriors and then Brookline would take over.

On the final leg, Nagle received the baton, dug in, and pushed, overtaking her counterpart to finish third, two places ahead of the Minutemen, giving Brookline 62 points and the Division 1 championship, the program’s first title since 1978.

“Honestly, I don’t like to lose,’’ Nagle said. “As our coach says, be a predator and as long as you push it is alright.’’

The Lowell boys’ team also had a strong start and hung on to win the Division 1 championship with 84 points.

First, in the 55-meter dash preliminary, senior Richmond Kwaateng tied a meet record (6.41) before winning the final heat and beat the meet record with a time of 6.37 seconds.

“I didn’t know what the meet record was at all,’’ Kwaateng, who will run at the University of Connecticut.

“The prelim felt good because I think it was my fastest prelim and it just carried on to the finals.’’

The Red Raiders were not done. In the 55-meter hurdles, senior Samuel Mutiso set another meet record, finishing his race in 7.47 seconds.

Following the dash, Kwaateng broke another meet record in the long jump, leaping 23-0¼ feet. His night was not over. He helped Lowell win the 4x200-meters relay (1:30.41).

“Great athletes like that like these meets,’’ Lowell coach Scott Ouellet said. “They want to do the best in, so they get that little extra bump of adrenaline.’’

Brookline began with junior Jamie Chamberlain winning the 55-meter hurdles (8.31).

“I could hear people cheering,’’ said Chamberlain. “Actually, during the race I could hear my coach and some of my teammates and I said to myself, ‘Oh my gosh they are watching. I need to go faster.’’’

After Chamberlain’s win, junior Sarah Schlosberg (7.46) and sophomore Annabel Cloney (7.50) continued the Warriors’ strong start by finishing 1-2 in the 55-meter dash.

As the meet continued, so did the wins for Brookline with Chamberlain winning in the long jump (18.05 feet) and Nagle placing first in the 1,000 with a time of 2:59.57.

John Hand can be reached at john.hand@globe.com.