Teams with great defenses tend to pile up close wins.
This sentence got me thinking, so I did some quick research using PFR's game finder tool. You can try to brush this off as simply a team with a great defense winning a lot of close games, but the number of close games Denver has played, as well as their record in those games, is anything but typical.
Thirteen of their seventeen games have been decided by 7 points or less, with Denver winning ten of them. Only two other teams since 1970 have had 10 or more wins in games decided by 7 or less in a single season (including playoffs): the 2003 Panthers and the 1978 Oilers, each of whom also had ten. A Denver win by 7 or less today and/or in the Super Bowl would set a new record.
Their total of thirteen games played that were decided by 7 or less has only been surpassed by three teams since 1970: the 2003 Panthers, the 1996 Jaguars, and the 1995 Colts, all of whom played fourteen such games. There have been twelve other teams who played thirteen such games in a season, most recently the 2011 Cardinals.
Denver's winning percentage in these games (.769) is currently tied for 4th best since 1970. The only teams that have done better are the 1999 Titans, the 1986 Giants, and and 1981 49ers, all of whom went 9-2 (.818) in those games. All three of those teams played in the Super Bowl, with the Giants and Niners winning. The 1978 Oilers were the other team to go 10-3 in these games. They made the AFC Championship, losing 34-5 at Pittsburgh.
Since this is something of an arbitrary endpoint, I wanted to see how the numbers would change using different values. Changing the numbers to 8 didn't make much of a difference. It puts Denver tied for second-most such games in a season and puts them second in winning percentage.
Now, changing it to 6 or less does make a difference. All of the sudden Denver plunges down to 9 such games, though their winning percentage in those games (7-2, .778) still puts them in the top ten of all-time.
If you change it to 3 or less, Denver falls off of the list entirely. (Though I couldn't help but notice that the 2013 Patriots were on it, going 6-1 with the only loss being @NYJ in the bogus field goal penalty game.)
Denver has played a historically high number of games decided by 7-8 points or less, and they have won most of them. But I don't think one can simply say that teams with great defenses tend to win a lot of close games. Looking at the list of teams that pop up throughout these lists is hardly a who's who of great D's throughout the years. It's the combination of Denver's great defense along with their poor offense that causes them to play so many close games.
The original search on PFR can be found
here.