NORTH CALDWELL, N.J. -- West Essex entered Friday night’s playoff game with South Plainfield with the state’s longest active winning streak of 18 games.

That streak is no more as the seventh-seeded Tigers (5-4) held on to upset second-seeded West Essex (8-1), the No. 10-ranked team in the NJ.com Top 20 and No. 15 in the USA TODAY NETWORK New Jersey statewide Top 20, 17-16, in the first round of the North Jersey, Section 2, Group 3 tournament.

West Essex, the defending sectional champs, saw its kicker Patrick Delehanty miss a 33-yard field goal in the closing seconds. South Plainfield took over with six ticks remaining and kneeled down to run out the clock and start the celebration.

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“It was a huge win for our program,” South Plainfield head coach Gary Cassio said. “No one believed we could knock off the defending state champs and No. 10 team in the state except the players and coach in the locker room.”

West Essex took over for its last possession with 1:35 left. The Knights started to drive down the field thanks to numerous chunk plays of over 10 yards running and passing. On second-down-and-four from the Tigers’ 45-yard line, West Essex completed a short pass and Sammy Nieves tackled him in bounds. The officials couldn’t agree on where to spot the ball and stopped the clock with 50 seconds to go.

Will Perez then took a sweeping handoff nine yards and later got down to the 15-yard line. After a spike on first down, West Essex threw two incompletions and then sent out the field goal unit. Delehanty had plenty leg, but the lefty hooked the kick to the right.

“I was a little upset that prior to the kick, they had no timeouts left with under a minute in the game and we tackled the ball carrier in bounds and the officials stopped the clock because they disagreed on the spot. That saved them 20 seconds of play clock and basically gave them another timeout. Game should have been over (if you add in the plays that occurred afterwards),” Cassio said.

Perez scored on a short 1-yard touchdown run with 5:38 to go to make it a one point game at 17-16. The drive came on the heels of a short South Plainfield punt. On the first extra point, South Plainfield jumped offsides which even though Delehanty made the kick, the play was blown dead. That actually worked to the Tigers’ favor however as on the next try, the holder bobbled the snap and tried to reach the corner of the end zone on the ground but was stuffed by South Plainfield at the 1-yard line.

“They had a ‘fire call’ and we were able to make a great play and hold them,” Cassio said.

South Plainfield scored all of its points in the first half.

Nieves, the quarterback, had a 41-yard rushing touchdown and a 66-yard rushing score. Ashwin DeGroot, who made both extra points, also kicked a 29-yard field goal as time expired in the second quarter.

“Sammy was huge in this game,” Cassio said. “He told us early in the week he believed we could win against a heavily favored opponent. He and those kids believed they could beat West Essex and they did.

“Ashwin gutted it out tonight. He got injured last week against Carteret and we weren’t sure if he was going to play. Not only did he play through his pain, he never came off the field and was our work horse offensively. Those kicks were right on point, too.”

DeGroot’s field goal proved to be the difference and the defense gave him that opportunity as Zach DelVecchio and Luke Nieymeyer sacked the Knights’ quarterback on third down on the previous West Essex possession.

South Plainfield ate up a ton of clock and converted two fourth-downs before DeGroot made the kick.

TJ Massaro and Brian Maszaczak made 12 and 10 tackles respectively while Niemeyer had nine, Tate had eight, and DelVecchio finished with five.

West Essex came into the contest averaging 40 points per game.

“Our kids play defense like they’re in a street fight,” Cassio said. “They fly to the ball and love to hit people.”

The Tigers needed everything to fall into place in the final week of the regular season just to make the playoffs. And now that they’re here, if the win over West Essex tells you anything, they are here to stay. The tough schedule against the likes of Greater Middlesex Conference foes St. Joseph (Met.) and Colonia and bigger schools in the Mid-State 38 in North Hunterdon and Linden prepared South Plainfield for the postseason.

South Plainfield will face third-seeded Rahway in the sectional semifinals next weekend in Rahway.

“We may be undersized against these bigger school, but nobody has more heart than my boys,” Cassio said. “They always believe they can play with anyone. Complete team effort tonight.”

Follow Chris Nalwasky on Twitter @ChrisWasky.