"Defense wins championships." 

In North American sports we hear that phrase often. We tend to hear it a lot more in football, but it also applies to basketball.

We may not see that same belief play out as much in today's NBA -- with the Golden State Warriors' elite offense and all -- but that same smallball culture hasn't quite made it to college basketball on a similar scale yet.

Grind-it-out defensive teams are still oh so relevant in college hoops. In fact, all four 1 seeds in this year's tournament rank among the top 78th percentile of defenses in the country.

With that being said, who are the top five defenses in the tournament?

In order to narrow it down to just five, I sorted and re-sorted through our power rankings, using our nERD and Defensive Efficiency metrics to point me in the right direction. I also took into account their opponents' Effective Field Goal Percentage and team fouls per game. 

One thing you'll notice though is that the top teams in Defensive Efficiency aren't at the top. That's because I also took our Consistency numbers into account, weeding out those teams that have had mere flashes or runs of good defense while also experiencing lapses throughout the year as well.

Now that you know the process, here are the results.

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Virginia Cavaliers

As I said, built upon the Bennett family's pack line defense, Virginia has been a defensive juggernaut over the course of the last five seasons. This year, they're up at the top yet again, in large part due to their Consistency (85th percentile).

The Cavaliers rank in the 87th percentile of all teams defensively and are among the top 25 teams in the NCAA tournament in terms of Defensive Efficiency. Their distinct ability to force tough shots -- as evidenced by their opponents' Effective Field Goal Percentage of 48.7% -- without fouling (just 16.4 team fouls per game) and without going for steals (5.5 per game) is the reason why the Hoos are a force to be reckoned with for opposing offenses.

Oregon Ducks

Despite the top seed, the Ducks may come as a surprise to many here. I mean, they're the 20th best offensive team in the country and just the 64th best defensive team, according to our numbers. However, even at their above average Pace, the Ducks hold their opponents to 69.4 points per game on an Effective Field Goal Percentage of 49%.

Other tournament teams possess those same kind of numbers, but Oregon separates themselves in blocks and steals, averaging 5.8 and 7.6 per game, respectively. With the Ducks you know what you're getting a nightly basis as well. They are among the top 12% of teams in Consistency rating.

Seton Hall Pirates

The Seton Hall Pirates are the first of five teams not to be handed a 1 seed by the Selection Committee this year. As a 6 seed, the Pirates are a very dangerous team to come up against because they always bring it defensively. They rank in the 92nd percentile in Defensive Efficiency while also cracking the 90th percentile in Consistency. 

At the bedrock of their sucess, the Big East champions have stymied opposing teams all season by challenging shots. As a team, the Pirates block 4.7 shots per game and hold opposing offensive attacks to a measly Effective Field Goal Percentage of 45.3%.

Saint Joseph's Hawks

We journey even further down the seed lines before coming to the 8-seeded Hawks. Saint Joe's gives up nearly 70 points per contest, but they, like Seton Hall, are also an above average team in Pace. As we go next level into the numbers, we see why the Hawks rank in the 92nd percentile of teams in Defensive Efficiency.

A la Virginia, Saint Joe's knows how to contest shots at an elite level without fouling. They average the fewest amount of fouls -- 16 per game -- of the five teams listed here all the while limiting their opponents' output by holding them to 31% from three-point land for an Effective Field Goal Percentage of 47.9%.

Providence

When most people start talking about the Friars the first thing to come out of their mouth is about their outstanding duo of Kris Dunn and Ben Bentil and how great they are at scoring the ball. That is a misguided view because the Friars rate in the middle of the pack in Offensive Efficiency but find themselves in the 83rd percentile of NCAA defenses. How?

Across the board, Providence is solid. They allow opponents an Effective Field Goal Percentage of 48.8% as they produce pressure on the defensive end of the floor. Led by the aforementioned Dunn and his 2.5 thefts per game, Providence secures 6.6 steals as a team. Their Consistency rating (87th percentile) proves them to be one of the most consistent teams in the field.