Last Wednesday night, there was a moment when Carlos Gonzalez probably thought he might be able to come up big. Down two runs with two out in the bottom of the ninth, Charlie Blackmon had managed to single off of Dodgers' closer Kenley Jansen just before CarGo stepped to the plate, and with a man on, one swing of the bat could've tied the game.

Then reality set in. The count went quickly to 0-2, and in that situation, Gonzalez was likely going to strike out. That isn't an indictment of CarGo, just a statement of fact: Jansen strikes out 42.5 percent of all the batters he faces, and that figure rises to almost 67 percent after he's ahead in the count 0-2. After managing to take a close pitch and foul another off, Gonzalez got a rare Jansen slider he couldn't handle:

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We often get used to dominant relievers being consistently great. For the elite guys, the end of the game is almost automatic most days, and the warm and fuzzy feeling you get as a fan knowing you have proven options at the end of a game is a special one. However, sometimes we need to take a step back and measure the ridiculousness of the stats some of these great relievers are producing.

And so we have Jansen. We know he's great. He's been great for a few years now; with his almost sole use of a hard cutter, it's easy and fun to compare him to a version of Mariano Rivera. With that lofty comparison made, it might not be surprising that he's putting together a very unique, special season.

Consider this fact: Jansen went the first month and a half of his season without walking a batter. He was injured for April, but after he debuted in mid-May, he didn't issue a walk until June 28th. During that time, he struck out 26 batters in 15.2 innings. That's a mind-boggling mix of dominance and control, and it's formed the basis of what Jansen has become in 2015.

Jansen is the current season leader of a very useful statistic: strikeout rate minus walk rate (K-BB%). K-BB% is a quick way of getting a good look at a pitcher's overall performance, as it's the stat that comes closest to roughly estimating a pitcher's ERA. It's obviously not perfect -- one fairly simple statistic is always going to have trouble encapsulating the many factors that go into a pitcher's overall performance -- but it works quite well in a back of the napkin situation.

Even if K-BB% isn't perfect, a pitcher is doing a lot of things right if they find themselves toward the top of the K-BB% leaderboard, as they're striking a lot of batters out while issuing very few walks. Last year we had Aroldis Chapman, Andrew Miller, Sean Doolittle, and Brad Boxberger as the leaders in K-BB% as relievers, and we know they are some of the very best late-inning pitchers in baseball. We still have a few of those names this year, but with one big change. Take a look at the top 10 for greatest K-BB% in 2015 among qualified relievers:

You could say Jansen has joined the club, but that's an understatement: he's leading the pack by a wide margin. The thing that makes Jansen special is that he's been able to limit his walks so effectively this season. To strike a ton of batters out, you usually need to throw hard. When you throw hard, you have a more difficult time controlling where the ball goes. Very few pitchers are able to hold these two opposing forces in balance; Kenley Jansen seems to now be one of them.

To further illustrate the excellence of Jansen's season, let's take a look at the 10 best seasons for K-BB% since 1990 (relievers only):

Not too much of a surprise -- we only have pitchers from recent seasons. The nature of the strikeout has changed drastically in the past decade, which is what makes comparing this era to other eras difficult. Still, we have some incredible company here: there's Craig Kimbrel's outstanding and unhittable 2012 (which may be at the top of this leaderboard for some time), a couple of Chapman seasons, and Eric Gagne's famous 2003 Cy Young campaign. Billy Wagner and Brad Lidge are the only two older pitchers who can really hold their own in the face of the incredible strikeout rates of the past few years, so we should give them a little extra credit where it's due.

By far the most remarkable element of Jansen's season is the way he's gone about putting up these numbers. Here's the rate at which he's thrown his cutter every year since coming into the league in 2011: 73.3 percent (2011), 89, 85.9, 83.5, 85.1. He has a small percentage of pitches that were classified as four seam fastballs (usually between 5-10 percent), but they could very well be misclassifications, meaning his rate of cutters could be slightly higher. Jansen strikes out over 40 percent of the batters he faces with basically one pitch. His slider is good (as we saw above with the CarGo strikeout), but he only uses it about 10 percent of the time. This is almost all about the cutter.

Does the fact that he has such dominance with one pitch make Jansen's cutter among the best pitches in the game? Perhaps. By run values among relievers, there are many better fastballs considered better than Jansen's, but they're thrown by guys who normally have at least a few more pitches. The only other reliever who relies on one pitch as much as Jansen does is Zach Britton (who throws a sinker), but he hasn't posted anywhere near the unbelievable strikeout rates that the Dodger's right-hander has this season.

In Jansen, we have a rarity: a preternaturally dominant closer who relies almost entirely on one pitch. In 2015, he's taken a leap forward, cutting his walk rate while increasing his strikeouts, vaulting him into rare territory among the best strikeout/command relief seasons in the past two decades. For the Dodgers, the steadiness of their closer has been a welcome trend in a season filled with a few bullpen problems. For Jansen, he'll keep doing what he always has -- cutter, cutter, cutter. Just like Mariano Rivera, everyone knows what he's going to throw, and they still can't hit it.