The Phillips Exeter Academy running back was virtually unstoppable in yesterday’s 129th meeting of the longest continuing prep school rivalry in the nation played at rain-swept Phelps Stadium. The Big Blue still hold the overall lead in the series, 68-51-10.

Scyocurka ran over and through the Big Blue for an unprecedented 346 yards on 31 carries and three touchdowns in leading the Big Red to a 31-14 victory.

Exeter (9-0) moves on to the NEPSAC Class A championship next Saturday against an opponent and site to be determined today. The Big Blue complete their season at 3-2-1.

“I thought [Exeter] really executed today,’’ said Andover coach Leon Modeste, who has lost to his archrival two consecutive years. “They’re a good team and that’s why they’re undefeated. We hung with them for a while but they beat us down. But they play as a team and you can see how well they work together on the field.’’

Scyocurka, a post-grad who came to Exeter after a stellar career at Longmeadow High where he was a primary factor in helping the Lancers win four consecutive Central/Western Mass. Division 1 Super Bowls, showed tremendous patience against Andover as he waited for his offensive line to secure blocks against a vaunted defensive front.

“Whenever the line performs and creates those holes there is going to be opportunities for me at any point in the game,’’ said Scyocurka, who has scored a school-record 30 TDs this season. “They did just that. Whenever there was an opening we were able to capitalize and get some points on the board. It’s just a wonderful environment here to be a part of this tradition. It’s an incredible feeling and rain or shine it didn’t matter today. I’m just blessed to be a part of this program.”

The rain never bothered the Exeter offense as it jumped out to a 14-0 lead with 7:45 remaining in the second quarter. A 65-yard jaunt by Scyocurka at the 6:11 mark of the first had the Big Red in front. Then, after a 15-play drive, Scyocurka would cap it off with a 1-yard plunge. Having won their last two games, the Big Blue refused to go away. Behind quarterback Andrew Vailas (12 of 22 for 152 yards, 1 TD), Andover stormed back to cut the deficit to 7 following his 3-yard carry over the goal line with 4:36 to go in the half. A few minutes later, following a punt, back came the Big Blue. A 33-yard completion from Vailas to Clayton Cleveland set up an Ed von Kuhn 12-yard scoring reception and suddenly the Big Red found themselves tied at 14.

Despite the score, the momentum never shifted in Andover’s favor. When Exeter got the ensuing kick, it marched to the Big Blue 38. Dan Guadagnoli hit David Mothander with a pass over the middle and the senior did the rest, beating two defenders to the end zone with 40 seconds left. The Big Red took a 21-14 lead into intermission.

That score took the life out of Andover as it never recovered. Mothander hit a 22-yard field goal to push Exeter’s advantage to 24-14 midway through the third quarter. From there, Scyocurka did the rest as his time-consuming runs kept the Big Blue offense off the field. Scyocurka added a 33-yard scoring run in the final minute of the third.