For more than 30 years, a 2-0 start was a sign of inevitability in Miami.

The Dolphins, first of Don Shula, then of Jimmy Johnson and Dave Wannstedt, won their first two games of the season 17 times between 1972 and 2002, and they made the playoffs 15 times. And in one of the times they didn’t — 1977 — they still finished 10-4 and missed the postseason only because of a tie-breaker loss to the Colts and a really good wildcard team (the 11-3 Raiders).

After four straight winning seasons, the Wannstedt era ended unceremoniously with a 4-12 dud in 2004, and the franchise officially wandered into the wilderness. Since then, the Dolphins have made the playoffs only twice, and in both seasons they had to rip off crazy, unlikely late hot streaks to do the deed — a 2-4 start begat a 9-1 finish in 2008, and a 1-4 start led to a 9-2 finish in 2016.

Since Wannstedt left Miami, the Dolphins have twice began seasons 2-0 (2010 and 2013). It meant nothing both times.

Does it mean something in 2018?

Miami has begun this season with tight wins over the Titans (27-20) and the Jets (20-12). The Phins are, at the moment, in first place in the AFC East. They host the winless-but-unlucky Raiders on Sunday with a chance to move to 3-0 for only the second time since 2002.

Here’s what we know for sure about Adam Gase’s team: it can defend. The Dolphins have allowed just a 35.1 percent success rate so far this season, fourth in the NFL and second among teams that haven’t plumped their stats by playing either Buffalo (Baltimore is first) or Arizona (Washington is third). They are first in standard downs success rate (31 percent, more than three percentage points ahead of anyone else), leveraging opponents into awkward downs and distances.

Granted, they’re also last in the league in passing downs success rate (42 percent), letting opponents off the hook pretty frequently. But force enough third-and-longs, and that ceases to matter. Somehow the Dolphins let Ndamukong Suh go to the Rams, and both defenses got better, at least so far.

We don’t know what Miami has to offer offensively just yet, however. The run game has been ultra efficient, with Kenyan Drake and Frank Gore (and, on occasion, quarterback Ryan Tannehill) contributing to a 45.2 percent rushing success rate, second in the league. But big plays have been lacking, and the team’s 36.7 percent passing success rate (23rd) is pretty awful.

In 2018, you’re not supposed to be more efficient on the ground than through the air. PFF has graded Tannehill as the league’s No. 19 QB so far, and it would probably be lower if not for a few rushing contributions.

So fine, there are questions. But it’s better to have questions at 2-0 than 0-2. And Miami doesn’t have nearly as many issues as a couple other unbeaten teams.

(For background on these stats, check out this piece on good 0-2 teams.)

Using second-order wins — a measure derived from post-game win expectancy, in which I basically toss key stats into the air and derive that a team could have expected to win this game X percent of the time — as a guide, we see that the Dolphins have one of the more legitimate 2-0 records so far.

Their post-game win expectancy was 87 percent against the Titans and 65 percent against the Jets; that adds up to 1.5 second-order wins, just a little bit behind the Rams (dominant but aided by turnovers luck) and Bengals (slightly less dominant, slightly less aided by turnovers). They are even with the Jaguars in this regard, and while the Jags have dominated the efficiency side of the game (which is the most sustainable way to win), they are vulnerable to big plays.

The Dolphins are also not as one-dimensional as the Chiefs or Bucs (either of whom might have the league’s best offense and worst defense at the moment), and they haven’t gotten by with quite as much smoke and mirrors as the Broncos.

You could make the case that the Rams and Jaguars are the class of the NFL so far. But among undefeateds, Miami’s path to 2-0 has been as legitimate as anyone else’s. The passing game clearly needs to pick up some steam, but the defensive success appears sustainable — the passing downs success rate is as or more likely to improve as the standard downs success rate is to regress.

Football Outsiders currently projects the Dolphins with a 63 percent chance at a playoff bid, second best in the AFC. Beat Oakland on Sunday, and Miami might become the surest thing in the conference.