Nick Saban looks at a play from Alabama's opener against Duke and breaks down one of the Crimson Tide's RPO plays. For more Detail, sign up for ESPN+ at https://plus.espn.com/ (1:30)

When Alabama went all-in with the run-pass option offense under quarterback Tua Tagovailoa a season ago, everything changed.

With a stable of powerful running backs and three NFL-caliber receivers in Jerry Jeudy, DeVonta Smith and Henry Ruggs III to spread the field, what was a defense supposed to do?

Well, not much, apparently. From 2018 until now, no FBS team has scored more points than the Crimson Tide (1,073).

In the latest edition of Detail on ESPN+, Alabama coach Nick Saban breaks down the strategies and concepts of the RPO offense from both sides of the ball.

Detail: Nick Saban The ground-breaking sports analysis program, brought to you by five-time NBA champion Kobe Bryant, continues with a college football edition, hosted by Alabama head coach Nick Saban. Watch on ESPN+

"That's what these spread out formations do: They make the defense declare itself," said Saban, a former defensive coordinator who still coaches defensive backs during practice.

Throughout the four-part series, whose first episode will be released Tuesday, Saban dives into that pre-snap thought process on offense and how Tagovailoa is able to decipher where to go with the football so effectively.

During one such play against Duke, Saban shows how Tagovailoa reads a blitzing outside linebacker and high safety coverage, opts against a handoff to the running back and instead throws a quick so-called "smoke" pass to Smith, which he turns into an easy gain of 9 yards.

And that was only a tame example. Alabama, which averages an FBS-best 9.5 yards after the catch per reception this season, has made a habit out of turning short, high-percentage passes into long gains.

"It used to be a lot more closed formations," Saban said of the way offenses have changed. "Now everything is spread and open. I think space play is much more important than it used to be years ago. People throw a 2-yard pass on an RPO and it turns into a 70-yard play.

"The game has just opened up to where horizontally and vertically you've got to cover the entire field. In the old days, I don't think it was really that way."