Discomfort was setting in.

Drew Griffith reminded himself why he was willing to endure it.

“You’ve done this before,” he thought as he rushed around the 200-meter oval during Sunday’s New Balance Nationals Indoor track and field championships in Boston.

The cue helped the Butler senior do something no other United States high school runner has. He set the national indoor two-mile record with a time of 8 minutes, 34.91 seconds.

Edward Cheserek, of New Jersey’s St. Benedict Preparatory School, previously calibrated the top mark at 8:39.15 in 2013. Due to a technicality, Griffith informally bested that by running the 3,200 meters in 8:38.67 at the University of Notre Dame’s Alex Wilson Invitational last month.

“The track was 310 meters instead of 300 meters, so the national association track committee would not give him the national record,” Golden Tornado track and field coach Mike Seybert explained.

It was a situation Griffith understood entering the competition. That awareness didn’t dull the sting after, though.

“It definitely kind of stunk at the time,” Griffith admitted. “Going into it, I did know that if I happened to break the national record, that it wouldn’t count because of the oversized track. I definitely had that on my mind going into this race and just was really gunning for that official national record.”

Griffith was initially set on running the 1,600 meters in Beantown. He changed his mind and, this time, he wouldn’t leave even a shadow of a doubt.

“He said, ‘Well, I’ll just go do it again,’” Seybert said.

While Seybert watched a live broadcast from home, Butler cross country coach Rick Davanzati was able to see the impressive performance in person. It came as no surprise to him.

“Knowing him, any time that he’s faced some adversity — and I’ll call that a little bit of adversity — he has come back stronger,” Davanzati said. “When he was a junior in cross country and lost the state championship, the boy, Brian DiCola from Hatboro Horsham, that beat him didn’t beat him the rest of the year in cross country.

“If he has a little bit of a setback, it just makes him all that much more determined.”

Marcus Reilly, a Michigan commit and senior runner at Massachusetts’ Northbridge High School, served as the race’s pacer for the first mile.

“He took Drew through the mile in 4:19,” Davanzati recalled. “You could see that they were moving fast, but Drew looked comfortable there doing that. When Marcus stepped off the track, Drew continued on his own. At that point, I would say they already had a 50-meter lead on the pack.

“Over the next half-mile, Drew continued to pull away. With 800 meters left to go, you could see that the race was an effort on Drew. ... He still looked strong and his splits that were being shown up on the board indicated that he wasn’t slowing down at all.”

Seybert urged his standout track athlete around the track from his kitchen.

“In a race, you hope a runner can hold the pace or the time he’s going out after,” Seybert said. “He just looked — as he has the whole year — he just looks totally in control of what he’s doing. If you watch an athlete since their freshman year, you can tell if they’re locked in.

“He just looked totally relaxed and smooth.”

In reality, Griffith was convincing himself to push through.

“Each lap, you just slowly try to relax and tell your body you’re not hurting as much as you actually are,” Griffith said. “With 400 (meters) left, it’s kind of tough to say ‘You’re not hurting’ to yourself, just because of how bad it hurts after 2,800. ... I was really trying to just close as hard as I possibly could.”

That showed in his final split.

“His last 400 was somewhere around 61.5 (seconds) or so, which is fantastic to finish that race at that pace,” Davanzati said.

When the timer finally froze for Griffith, the result blew Seybert away.

“I thought that he would break this record, but I didn’t think that he would go five seconds under,” he marveled. “Five seconds on a track is huge.”

From close by, Davanzati confessed it made him emotional.

“That was just amazing,” Davanzati said. “He never ceases to amaze me (with) how he’s so consistent. It’s a boy that I see every day in training. He does all the right things and it’s paying off for him.

“Today, this national indoor record is just a fantastic accomplishment.”