In the NFL, teams only get a dozen or so possessions each game with which to score points. Unfortunately, most coaches never remember that until they've wasted most of them. In the fourth quarter, conservative-to-a-fault coaches who punted away points and dawdled minutes off the clock become desperate, reckless aggressors.

Every week at VICE Sports, Inopportune Knocks will take a hard look at first-half opportunities NFL teams passed up—sealing their second-half fates.

PITTSBURGH STEELERS 38, OAKLAND RAIDERS 35

Generally, Inopportune Knocks looks at fourth-down decisions, but this week a coach abandoned a drive on first down—and in doing so, made your humble columnist double over in disbelieving grief.

Following a Steelers field goal that put the Raiders down by a score of 21-14, the Raiders took over on their own 20-yard line with 29 seconds left on the clock. Just 27 yards away from setting up kicker Sebastian Janikowski's for an attempt that would match his career long, Raiders head coach Jack Del Rio simply chose not to.

Dear reader, I want you to enter the theatre of your mind.

Imagine that it is the fourth quarter of a very important game, and the Raiders need a field goal to win. Taking over on their own 20-yard line with 29 seconds left on the clock, they snap the ball, take a knee and walk off the field willing losers.

Del Rio would be lucky to coach another NFL game. Yet the opportunity he passed up at the end of the first half is no different than if it had been at the end of the second—and for want of one more field goal, the Raiders lost a game with massive playoff implications.

TENNESSEE TITANS 34, NEW ORLEANS SAINTS 28

Sometimes coaches make decisions that are so far off-base, you wonder what information they're actually using.

Mike Mularkey, a well-regarded assistant with two poor head-coaching stints under his belt (48 games and a .333 win percentage) was in his first game as Tennessee Titans interim head coach, having taken over for the fired Ken Whisenhunt.

Things were not going well for the 7.5-point underdog Titans. Their first offensive drive under Mularkey was a three-and out, and in their their first defensive stand, they allowed a touchdown.

Their second offensive drive was also a three-and-out (they actually went backwards), but the Saints muffed the ensuing punt. The Titans had the great fortune to recover the fumble, and ended up on the New Orleans 42. After a nine-yard first-down run, they faced 2nd-and-1. Then 3rd-and-1. Then 4th-and-1.

The probability of a typical NFL team converting 4th-and-1 from their opponents' 33, per Brian Burke's 4th-down calculator, is 74 percent. The odds of converting at least once in three attempts, if we run Bernoulli trials, is therefore 98.2 percent.

98.2 percent.

Maybe Mularkey didn't believe in his offense, ranked 27th in yardage, even against a Saints defense that is ranked 31st. Instead of trying for one yard one more time, at a standalone success rate of 74 percent, Mularkey sent kicker Ryan Succop in to attempt a 50-yard field goal.

Succop famously hadn't missed a kick since early in 2014, but coming into yesterday's game he was 11-for-20 when kicking from 50-plus yards out. The fourth-down calculator says NFL kickers make about 55 percent of these tries; Succop, then, is perfectly typical.

Yet Mularkey turned down a 74 percent chance of extending the drive for a 55 percent chance at three points.

Decisions like this are just one reason why he's a well-regarded assistant, and a terrible head coach.

CINCINNATI BENGALS 31, CLEVELAND BROWNS 10

Browns head coach Mike Pettine has earned praise in this space for his willingness to play the actual percentages. But during this critical Thursday Night Football rivalry matchup, Pettine turtled.

Quarterback Johnny Manziel, getting his second of what will likely be quite a few starts this season, had been impressive early, keeping the game close with a great on-the-run touchdown pass. The Browns, whopping 13-point underdogs, had gone into halftime down just four points.

Regular readers are already crying foul; Inopportune Knocks usually looks only at first-half possessions. But the Browns' first possession of the second half is a perfect illustration of how NFL coaches don't value their most precious possession—possession itself—and let fear drive them to pass up opportunities in favor of losing gracefully.

Just over five minutes into the second half, Manziel made a brilliant up-the-middle scramble on 3rd-and-12, wisely deciding to surrender himself at the end of it. Not-so-wisely, he slid right at the sticks rather than beyond them—and after an initial ruling that he'd converted, a Marvin Lewis challenge revealed the ball was inches short when Manziel hit the turf.

Yes, the Browns were backed up on their own 21-yard line, but 4th-and-short is 4th-and-short:

Win Probability: 28 percent

Adjusted Win Probability: 13 percent

First Down Success Rate: 74 percent

So, about that adjusted win probability of 13 percent: Vegas spotting a team 13 points is equivalent to a pre-game AWP of 0.08. In other words, the wiseguys thought the Browns had just an eight percent chance of winning this game.

Even more importantly, this game was against the leaders of the AFC North. A win would put the Browns up 3-6 and drop the Bengals to 7-1; with eight weeks left their playoff chances would be small but extant. A loss, however, would end their season.

Brian Burke's WP model calculates the break-even point at just 55 percent, and his expected points model puts it at 60. NFL teams convert 74 percent of these opportunities; it's an on-paper slam dunk.

Of course, the game isn't played on paper, and Manziel and the 29th-ranked Browns scoring offense against the Bengals' fourth-ranked scoring defense is far from league average vs. league average. Yet what choice did the Browns have? The best-case scenario for punting—a long punt and a quick stop—just winds the clock down a few minutes and puts them back where they were.

The Football Gods cruelly punished Pettine for his cowardice: Andy Lee, one of the better punters in the game, managed to send it just 28 yards downfield, and the Bengals got three points out of the ensuing drive. Manziel got the ball back, of course, on his own 20-yard line—this time, down by seven points instead of three.

Had the Browns gone for it and got it on their first second-half possession, their Adjusted WP would have risen to 16 percent, twice what it was at the beginning of the game. When they started that next possession, their AWP had fallen to 11 percent.

In the end, the Browns didn't get beyond their own 26-yard line until their final meaningless drive. By choosing to 'stay in the game' at the beginning of the second half, Mike Pettine punted away his last, best opportunity to win.

OPENING THE DOOR

Underdogs need to be aggressive to maximize their small chance at victory, and 49ers head coach Jim Tomsula is…. well, maybe wise is not the right word, but aggressive enough to realize this.

Already up 7-3 on Atlanta despite being underdogs by more than a touchdown, the 49ers were driving through the end of the first quarter. Facing a 4th-and-1 on the Falcons' nine-yard line, many coaches would have laid up and taken the field goal—but Tomsula and the 49ers went for it, and got it.

Three plays later, they capped the drive with their second touchdown of the game.

After scoring two touchdowns in the first quarter, they only managed one field goal the rest of the way…and yet, they won the game by one point. Tomsula knew, or at least intuited, that he probably wouldn't drive that far down the field very often with Blaine Gabbert at quarterback, and correctly chose to get everything he could out of the chance.

Well done.