That change was evident in training camp, and it was even more noticeable when the Eagles defeated No. 10 Florida State 28-13 in their season opener on Monday night in Tallahassee. BC had lost 12 of 13 games to FSU and hadn’t beaten a top-10 team in a decade, but none of it mattered.

The Eagles truly believed they were the better team, and it was easy to see why once the game started. They outplayed Florida State in the trenches, played disciplined football, and didn’t let the moment get too big.

“We’ve been planting trust all summer,” running back Kye Robichaux said. “We’ve been working hard. It’s been a grind. That’s where you see all the connections on the team. It’s just a bunch of dogs, man, dedicated to one goal.”

Here are five lessons you can learn from this convincing victory:

1. Discipline is a key component of O’Brien’s approach.

Throughout the camp, O’Brien rarely reprimanded players for physical fouls. However, when a player made a mental lapse, he didn’t hold back.

The Eagles took the constructive criticism graciously, trusting O’Brien’s qualities and believing that their daily improvements would pay off.

“He’s very honest, very sincere,” guard Ozzy Trapilo said. “Sometimes the truth is hard. He’s not afraid of it. I think that’s good for the guys on the team.”

When the Eagles played Florida State last year, they were the more explosive team, but a program-record 18 penalties tarnished an otherwise promising performance. And it highlighted a larger trend of the Eagles often getting in their own way.

Third-and-longs became the norm, winning the turnover battle was far from a given and open-field tackling became sporadic.

On Monday night, the Eagles were considerably more disciplined, prepared and savvy. They went 9 of 16 on third down and held the Seminoles to 3 for 14. They committed just one penalty, compared to FSU’s seven, won the turnover battle 1-0 and avoided any head-scratching moments.

2. The offensive line has the chance to be special.

During their five-game winning streak last year, the Eagles relied heavily on their offensive line and methodically wore down opponents deep into the fourth quarter.

Monday’s game followed a similar script, with a dominant possession period from 39:09 to 20:51. BC allowed FSU just 51 seconds of possession in the first quarter and never allowed the Seminoles to get comfortable in their own stadium.

Jude Bowry (left tackle), Dwayne Allick (left guard), Drew Kendall (center), Jack Conley (right guard) and Trapilo maneuvered FSU’s defensive line, which received much praise early in the season.

Granted, this FSU team may not have as much firepower as many expected, but BC’s rushing attack was praiseworthy nonetheless. The Eagles racked up 263 yards on the ground, compared to just 21 for FSU, and dominated the line of scrimmage.

Robichaux (19 carries, 85 yards, 1 TD), Treshaun Ward (12 carries, 77 yards), Castellanos (14 carries, 73 yards, 1 TD) and promising freshman Turbo Richard (4 carries, 28 yards) all created space with ease.

“Our running back room is as close as it can be,” Robichaux said. “We all feed off each other.”

3. Castellanos has changed his approach somewhat.

The more chaotic a play is, the more likely Castellanos is to make something out of nothing.

While he showed his agility on Monday, he played with more composure and took fewer risks than he did last year. It’s clear that O’Brien and quarterbacks coach Jonathan DiBiaso have been preaching the importance of appreciating the ball and not giving the opponent chances.

Castellanos made mature decisions, made the right reads and made life easy for his receivers. He finished 10 of 16 for 105 yards and two touchdowns and excelled in a more pro-style offense than BC used last year.

“I thought he controlled the game really well,” said O’Brien.

4. They handled the ebb and flow seamlessly.

The first 24 minutes were all BC. Florida State looked out of shape, not recording a first down until 6:13 into the half.

BC took advantage, building a 14-0 lead before FSU crumbled. The Eagles stopped two promising drives near the end of the half, holding the Seminoles to field goals each time.

Early in the second half, BC forced FSU into a fourth-and-5 from their own 47. The Seminoles decided to go for it, but quarterback DJ Uiagalelei made a special delivery straight into the hands of BC defensive back Max Tucker.

“That was probably one of the biggest plays of the game,” O’Brien said. “That really got us going in the second half.”

BC extended its lead to 21-6 with a 4-yard pass from Castellanos to Robichaux. When FSU cut it to 21-13 with 5:19 left in the third period, the Eagles responded immediately when Robichaux scored from 2 yards out four minutes later.

“That was a drive we had to answer,” O’Brien said. “They were kind of on a roll there. That kind of drive is big.”

The Eagles then turned the corner in the fourth quarter. This is a mature, experienced team that knows how to close out games.

5. It’s a big victory, but it’s only one victory.

O’Brien’s overwhelming feeling afterwards was that while this is a big step for the program, it is just the beginning.

It goes back to his philosophy of expecting to win. The Eagles celebrated, but they didn’t go overboard. This was part of the plan, and the first step is complete.

“It’s a really important win for BC and where we’re at right now,” O’Brien said, “but it’s just one game.”

Trevor Hass can be reached at [email protected].