In the blink of an eye, the St. John’s Prep soccer team scored the lone goal that secured its second Division 1 North sectional championship in the last four years.

The Eagles (19-0-3) were awarded a corner kick off a save by Brookline junior goalie Zach Macdonald in the 67th minute. Prep senior Mitch Collins’s bending cross found the head of classmate Erik Gustafson, who placed it to senior Steven Yakita. The striker didn’t miss the open net and his goal stood for the final 13 minutes in the 1-0 victory Saturday afternoon at Manning Field in Lynn.

Prep will play at South champion Brockton in a state semifinal Tuesday night.

“When you are undefeated and you are the No. 1 seed, there is that added pressure on the kids, and I think they were maybe feeling that today — especially in the first half,’’ said Prep coach David Crowell.

“But then they just stepped up and showed why they are undefeated and the No. 1 seed.’’

Fourteenth-seeded Brookline (10-6-6) controlled most of the play in the first 40 minutes. The Warriors’ tempo forced Prep senior keeper Cam Buckley to make six saves, but Buckley hurt his knee in an early collision, and he was replaced by Christian Buckley.

Christian, a junior, picked up where his brother left off. Buckley collected three saves — including two early in the second half to keep the game scoreless.

Prep began to force the play in the second half, and senior Sam Smith’s strike from just outside the box forced Macdonald to make a key save, his fifth of the day.

But the Eagles finally broke the ice on the ensuing set piece from the corner as Yakita extended his scoring streak to 18 games.

“I mean in all honesty, I didn’t even realize it went in until it hit the back of the net and after a couple of seconds,’’ said Yakita. “It’s unbelievable if anyone scores. I am just here to win the game and we got to keep moving forward.’’

Division 1 South

Brockton 1, Needham 0 — Senior Daniel Andrade chested home a cross from junior Edson Lopes in the 46th minute, propelling the Boxers (19-1-2) to the sectional title at Whitman-Hanson.

“We needed this big test to see if we are for real, and the boys responded greatly,’’ said Brockton head coach Herminio Furtado. “The confidence we have, I just wish that it continues.’’

Although Brockton raised the trophy, Needham senior keeper Andrew McNally turned in a consensus man-of-the-match performance.

In the 16th minute, McNally robbed Leonardo Teixeira at the goalmouth.

“We gave Brockton one heck of a battle tonight,’’ said Needham head coach Jimmy Odierna. “Hats off to Brockton for being an excellent team. We held them off for most of the game save for one big chance.’’

Division 3 South

Norwell 1, Dover-Sherborn 0 — A loose ball banged around the penalty area in the 7th minute of Saturday afternoon’s sectional final between Norwell and Dover-Sherborn, begging to be settled.

Junior Ethan Hayes answered the call for the No. 2 Clippers (18-2-2), rifling home the sole goal in a win over the No. 4 Raiders (15-3-4) at Whitman-Hanson.

Hayes’s strike booked his team a spot in the D3 state semifinals Nov. 14 at Manning Field in Lynn.

“It’s a typical win for us where we grind away and leave it on the field and play our hearts out,’’ said Norwell coach Jack Browne. “That’s our style, and we’re very, very proud of these guys. They’re all warriors.’’

Scoring chances were few and far between for Dover-Sherborn until the 77th minute, when senior defender Erik Linden bent a shot off the right post.

The Raiders largely controlled possession during the second half, with sophomore midfielder Adam Fam and senior forward Corey Lampman threatening the Clippers.

“The guys have nothing to be ashamed about with how hard they worked,’’ said D-S head coach Joe Gruseck. “When you get to tournament time, only one team is happy at the very end.’’

One year ago, Norwell lost to Medway in the D3 South final.

“We didn’t want to lose again, that was for darn sure,’’ Browne said. “The thought never occurred to us that we were going to drop this game.’’

Division 2 South

Oliver Ames 1, Nauset 0 — Senior Jack Carroll registered the shutout and then stopped Nauset’s third penalty kick as the Tigers (14-2-4) ousted the defending champions in the sectional semifinals.

Pembroke 3, Dartmouth 2 — Nate Horner scored two goals and Travis Smith added another for the Titans (13-3-5), who staved off a second-half rally to advance to the sectional final.

Preps

Berwick 2, Portsmouth (R.I.) 0 — Senior co-captains Brendan Tribastone and Zach Trotzky scored for the Bulldogs (9-5-3).

Roxbury Latin 3, Rivers 1 — Senior captain Matt Uek scored twice for the Foxes (7-6-2).

Middlesex 2, St. George’s 1 — Junior Josh Quirk (one goal, one assist) led the Zebras (12-1-4) past the Dragons.

Belmont Hill 1, Governor’s Academy 0 — Senior Cole Matthews provided the lone goal for Belmont Hill (12-2-3).

Jonathan Sigal contributed from Whitman-Hanson. For more highlights, go to bostonglobe.com/schools.