Bill Belichick wasn’t a football genius in 1975.

The New England Patriots head coach reflected on lessons he learned in his first job on an NFL coaching staff in a piece ESPN published Thursday morning. Belichick was just 23-years-old when Baltimore Colts head coach Ted Marchibroda hired him as a special assistant to the head coach. Here’s what Belichick learned, per ESPN:

“A lot of X’s and O’s, but it really wasn’t the X’s and O’s. It was a lot more about just being a professional coach — preparation, work ethic, dependability, what goes into having a good football team.

“We were 1-4 and won our next nine straight. It was a young team that got off to a slow start, but we gained our confidence, and it taught me a great lesson in football of just keep working, keep fighting, just one day at a time. Don’t worry about the record at the end of the year. Just have a good day, have another good day, win this week, and then move on to the next week. That’s what we did in 1975.

“They were 2-12 the year before. They were terrible. But Ted gave the team great confidence, great leadership. Ted is one of the most positive people I’ve ever been around, always confident. Even when it was fourth-and-17, he was always sure we were going to make the play or do what we need to do. He was such a great person for me. I lived with Ted. We stayed in the same hotel, drove him to work every day, drove him home every day. We had our staff meetings in the car. We ate breakfast together. He was such a mentor.”

ESPN shared a photo of what the greatest NFL coach of all time looked like in 1975.

Belichick’s look has changed, but the lessons he learned under Marchibroda endure to this day.

Thumbnail photo via Winslow Townson/USA TODAY Sports Images