NFL betting: Here's what we can glean from Week 1 of 2020

History repeats itself. Experience is the best teacher. There are a lot of sayings and clichés about how those who don't learn from their past mistakes are doomed to repeat them.

With Week 1 of the 2021 NFL season now upon us, why don't we take a look back at Week 1 of the 2020 season? What happened? What did we learn? How can we apply that to Week 1 of this season?

The spreads didn't matter much

In Week 1 of last season, you weren't sweating spreads much. In fact, only two of the 16 games had a final margin of victory that finished within three points of the spread. On average, the spread was off by more than eight points per game. Six games saw the spread be off by 11 points or more.

The spread only mattered in one game; when the Chargers defeated the Bengals by three points as a 3.5-point favorite. In every other game, the favorite either covered the spread or the underdog won outright.

What does this mean for 2021? For one, it seems like a good idea to avoid buying points or playing teasers in Week 1. The lines aren't as sharp as they will be as the season goes on.

Additionally, if you like an underdog, don't be afraid to play them on the moneyline. If you like the Browns getting 6.5 points from the Chiefs, maybe you can sprinkle some on the +225 moneyline.

Underdogs straight up

Underdogs went 8-8 against the spread in Week 1 of 2020. Of the eight underdogs who covered the spread, seven of them went on to win the game outright.

It didn't matter whether they were small underdogs or big underdogs. The Packers, Titans, Bears and Rams all won as underdogs of three points or less. The Jaguars, Cardinals and Washington Football Team all came through as winners despite being underdogs of at least 5.5 points.

If you like the Eagles as three-point underdogs against the Falcons on Sunday, you might as well throw some money on the Eagles to win the game outright at +140. Maybe the Jets have something to prove to old pal Sam Darnold? They're currently +185 on the moneyline as 5-point underdogs to the Panthers.

What about the totals?

Of the 16 games played in Week 1 of 2020, eight went over the total and eight went under the total. Eight games finished within seven points of the total, meaning the oddsmakers were much sharper in the totals they posted compared to the spreads.

Of the eight games that went over the total, they went over by an average of 10.4 points per game. Of the eight games that went under the total, they went under by an average of 8.1 points per game.

Sometimes, the oddsmakers get it very wrong. Green Bay and Minnesota combined for 77 points in Week 1 last season despite the total pregame sitting at 45.5 points.

However, for the most part, it might be a good idea to avoid totals in Week 1. There's a lot of relevant information that we don't have a complete grasp of going into the season, such as run/pass splits, pace of play and personnel usage.

In hindsight, some lines will look bad

Looking back at the lines from Week 1 of last season, some of them were shockingly way off based on what we saw unfold in the 2020 season. For example, the Packers were 2.5-point underdogs against the Vikings. Green Bay finished the season with 13 wins while Minnesota missed the playoffs with a 7-9 record.

We also saw non-playoff teams like the Cowboys, Broncos and Lions open the season as favorites over playoff teams like the Rams, Titans and Bears.

What does this tell us? We still have a lot to learn about these teams and what their fortunes will be in 2021. However, there's a good chance that some of these lines will end up looking ridiculous in hindsight. If you feel like you have a good edge, don't be afraid to take advantage. I assure you, a year from now, we'll look back at some of the Week 1 lines from this season with disbelief.

Do not overreact

There will be some shocking results during opening weekend that nobody saw coming. It seems like every season, there's a Week 1 game that eliminates half of those who are competing in survivor pools.

Last year, the Jacksonville Jaguars won their season opener against the Indianapolis Colts by a score of 27-20. The Colts were 7.5-point favorites. This was the only game the Jaguars won all season en route to the league's worst record. The Colts rebounded nicely, making the playoffs with an 11-5 record.

Additionally, the Cleveland Browns got smoked by the Baltimore Ravens in Week 1 last season. The Ravens won 38-6 as 7.5-point favorites. Despite the disgusting scoreline for the Browns and the immediate hot takes of whether the Browns should move on from Baker Mayfield, the two teams finished the season with the exact same 11-5 record.

Who knows what will happen? Maybe the Lions will beat the 49ers as 7.5-point underdogs. Even if that does happen, it doesn't mean the Lions will be good and it doesn't mean the 49ers' season is over. Absorb what happens, but don't overreact to a single result.