For high school football traditionalists, Round 1 of the MIAA­ playoffs was a foreign product unbeknownst to their defensive, grind-it-out based sensibilities.

Such is the new age of football, in which points abound and receivers run rampant.

In 64 games across Eastern Massachusetts last weekend, winning teams averaged 33.4 points, with seven eclipsing the vaunted 50-point threshold.

Chief among them was preseason darling Andover (4-4), which threw its way to a thrilling 54-48 overtime victory over second-seeded Lexington in Division 1 North’s first round. The win set up a much-anticipated semifinal matchup with third-seeded St. John’s Prep Saturday at 2 p.m.

“It was awesome,’’ said junior wide receiver Cedric Gillette. “Everyone was elated. I didn’t even want to leave the field. No one wanted to go home.’’

Gillette is representative of the transformation high school football has undergone from the days when spread pass attacks were atypical and the power run game was a coordinator’s desired scheme of choice.

After a lifetime of playing out wide, Gillette was thrust into the slot just five days before his first varsity game as a sophomore. Now, having a full offseason to perfect his route running and make gains in the weight room, the junior has emerged as a focal point of the most heralded pass game in Division 1.

Gillette’s breakout came at the perfect time on a damp night in Lexington. He had 10 catches and three touchdowns on 294 receiving yards. Gillette’s counterpart, quarterback EJ Perry, threw for five touchdowns to bring his season total to 33.

“Cedric has always been a guy who works tremendously hard,’’ said coach E.J. Perry, father of the quarterback. “He’s not an out-and-out burner but he’s fast enough. He’s really taken it upon himself to run really great routes in the slot. He’s really crafted himself. Getting [close to] 300 yards in one game is remarkable.’’

A knee injury to star wideout and Brown commit Dan Gemmell midway through the season left a void that may have proved insurmountable for a team lacking depth. Andover’s plethora of receiving weapons picked up the slack.

“When we heard that Dan was out, I immediately called [senior receiver Joe] Rockwell,’’ said Gillette. “Our attitude was ‘we’re going to step up.’ Joe and [John] Marotta and [Jack] Boese­ have done a great job stepping up. Coach Perry said to me, ‘It’s time to play the best football of your life.’ We were all crushed but we knew we could adjust with a quarterback like EJ and the receivers we have.’’

Having the younger Perry at the helm remains the key to Andover’s spread attack, as opposing defenders are left scrambling to contain a seemingly endless playbook of pass plays.

“In the spread, everything is about EJ’s reads,’’ said Gillette. “He always makes the right reads. I can’t tell you how many times I’d get a text from EJ this summer saying, ‘I’m over at the field, come throw with me.’ ’’

The routine paid off; twice in the second half Friday night Perry connected with Gillette over the middle on a route the Golden Warriors added at halftime. Gillette’s three touchdowns went for 85, 54, and 47 yards.

“Teams are terrified of EJ throwing the ball,’’ said Gillette. “Defenses have to spread out to cover the pass. EJ is an athlete and especially this year he has broken out some clutch runs. That’s the spread offense working.’’

Prep now looms with its two offensive stalwarts, quarterback Mike Yarin and receiver Hayden Rockett, game-time decisions with upper-body injuries.

“Prep is amazing,’’ said Gillette. “We’re going to play as hard as we can and see what happens. We’re not even supposed to be here. We’re playing with house money and that’s a dangerous thing.’’

In the second Division 1 North semifinal, two similarly dynamic spread offenses clash, with fifth-seeded Everett taking on top-seeded Central Catholic at Burlington High School Saturday at 5 p.m.

“They have guys that can score from anywhere on the field,’’ said Central coach Chuck Adamopoulos. “Their running backs do a great job of attacking the flank and the perimeter of the defense. Quarterback [Jordan McAfee] who has been good all along has really made great strides for them this year.

“If you don’t have disciplined pursuit angles and run to the ball you’re going to be in trouble. They’ve been one of the marquee programs in the state. If you want to get out of the north you have to go through Everett.’’

Owen Pence can be reached at owen.pence@globe.com.