Like one of his goals last year, Garbanzo executed a scissors kick and his goal gave the Trojans the game's first score.
"I knew we would score,'' Garbanzo said. "Coach (Dom) Wren changed our game plan at the half. We came out and perfected it; the goals kept coming. This feels like last year all over. I get to come back next year and it would be nice to win three straight."
Northwestern moved to 27-2, setting the school record for most wins in a season. Irmo, which came in ranked No. 1 and Northwestern No. 2, ended up at 24-2. The Trojans have played in five straight championships and have won four, including the last three.
It was Garbanzo again five minutes later. He took a cross from Dennis Moore and ripped another home for a 2-0 Trojans lead. It was his 39th of the season.
Irmo was still within fighting distance with 26 minutes left, but Foster scored unassisted at the 57:37 mark. His goal gave the Trojans what appeared to be an unsurmountable lead at 3-0.
"We missed some shots in the first half we should have made and it would have been a different game if we'd taken a 2-0 or 3-0 lead into the half," Irmo coach Phil Savitz said. "Northwestern seems to turn it on in big games.
"What they have done the last five seasons, winning four of five is the hallmark of a good program. Dom does a good job and has good players. I don't see much changing in the future."
Foster was in goal for the last two state championships. This year he was moved to forward because of his booming leg, the hardest kicker on the team.
"I'm speechless,'' Foster said. "I was the goalie when we won the last two, and was out on the field tonight. All I can really say is I'm proud to have been a part of this program the last four seasons."
But the Yellow Jackets were far from finished.
Irmo got on the board at the 67:03 mark, but for just a second it looked like another Sam Faris stop. Irmo's Joe Bivona launched a shot from 40 yards out. Faris caught the ball but lost his balance and fell inside the goal.
At the 71:44 mark, Irmo scored what was called an own-goal, meaning Northwestern knocked in the ball. But the goal went to Zach Akree, who got his foot on the ball before it found the net.
"We gave them two goals," Wren said. "Both of them shouldn't have gone in. But Irmo is a class program, one of the best in the nation. To score four goals against them in a single half is quite and achievement.
"We were the underdog, but I take pride in my kids and they take pride in our program. We came here to win, not just to play. It's starting to be that winning state championships is a legacy for Northwestern players."
It was 3-2 and the final 8:16 saw a constant Irmo charge at the Trojans' goal. At one point, the Yellow Jackets missed three headers and a kick from inside the box.
All hopes of an Irmo tie ended with eight seconds left when Moore scored off a double assist from Martinez and Garbanzo.
"We believed we could do it," Martinez said. "We didn't play like we believed in the first half, but we went out with a new plan in the second. Coach Wren told us to which players to check and told us to keep the ball on our forwards' feet. We went out and took care of business."
It was obvious after the first 12 minutes that Northwestern was in a fight for its life to win a third straight championship. Again a team dominated the early play, beating the Trojans to nearly every loose ball and making runs at Northwestern goalie Sam Faris.
Irmo had outshout Northwestern 6-0 and had a pair of corner kicks to none 15 minutes into the match. Not every shot was on frame, but those that were met Faris, who terminated all attempts that came his way.
The Trojans finally got on track with its first shot from Ricky Garbanzo at the 16:34 mark. It was on target, right into the waiting hands of Irmo keeper Rob Sullivan. Rejected or not, the attempt seemed to wake up the Trojans offense, which had been almost non because Irmo had kept Northwestern backing up and playing defense.
It was Garbanzo again at the 17:13 mark on a run from the right side. He kicked the ball and it was blocked. The ball came right back at Garbanzo, who banged his second kick off the right post. But the discovery of its offense helped the Trojans forced the Yellow Jackets to back-peddle and play defense.
Irmo's biggest defensive play of the half was courtesy of Northwestern. With just over 11 minutes left, Jeremy Dobbins fed Garbanzo a perfect pass on the right side from about five yards out. Garbanzo took the shot and rippled the back of the net at Sullivan's back.
Northwestern's fans stood and cheered, briefly. The official nearest the goal ruled the Trojans were offsides and the goal was disallowed.
NORTHWESTERN 4, IRMO 2
Second half
N - 41:32, Ricky Garbanzo, assist Ryan Foster
N -54:30, Garbanzo, assist Dennis Moore
N - 57:37, Foster, unassisted
I - 67:03, Joe Bivona, unassisted
I - 71:44, Zack Acree
N - 79:52 Moore, assist Alex Martinez, Garbanzo
Shots on goal: Northwestern 5. Irmo 6.
Corner kicks: Northwestern 2. Irmo 6.
Fouls: Northwestern 16. Irmo 18.
Goalies: Northwestern - Sam Faris (4 saves). Irmo - Rob Sullivan (1 saves), Stephen Arneson (0 saves).
Records: Northwestern 27-2. Irmo 24-2