When you think "rivalry," Cubs-Nationals doesn't necessarily come to mind. But a little over a month into the season, Chicago and Washington have the two best records in baseball and look a whole lot like two teams that could be destined to throw down in October.

Thanks to the scheduling gods, we don't have to wait until then, as these clubs are about to square off for a four-game series in the Windy City.

Hooray for baseball.

The Cubs, who already were good and then went out and signed Jason Heyward, Ben Zobrist, John Lackey, Willie Mays Hayes, Kelly Leak and Roy Hobbs (OK, I made up those last three), were expected to be really good. And they have been. Just ask the Pirates, a playoff-contending team that spent the past three days getting swept by Chicago to the tune of a 20-5 combined score.

Not to be outdone, the Nationals have gone 5-1 in the first six games of their magical Midwestern mystery tour, a grueling 10-game trip to St. Louis, Kansas City and Chicago that makes Lewis and Clark seem like homebodies. The latest "W" for the curly W's? A convincing 13-2 pounding of the Royals -- or as they're commonly referred to, the reigning World Series champs.

All of this is to say, the Cubs and Nats are both pretty darned good.

By the end of the weekend, we should have a better grasp on how exactly Joe Maddon's and Dusty Baker's clubs stack up against each other. But why wait until then when we can obsess over it now?

Here's a look at the Cubs and Nats, and how they compare:

OFFENSE

Kris Bryant & Co. are off to such a torrid start, their team OBP that is just five points lower than Bryce Harper's. Getty Images

The way Chicago's hitters have been producing, you'd think it was their final NBA game and opponents were just letting them score (Kobe conspiracy theory, anyone?). Just how prolific have the Cubs been? Their average run differential is more than three runs per game. And that's including losses. By comparison, the Nationals have outscored opponents by more than three runs in just eight of their 27 games.

Still, it's not as though the Cubs have been facing top-notch pitching. Seventeen of their first 26 games came against Arizona, Cincinnati, Colorado, Milwaukee and Atlanta, otherwise known as the National League's five worst pitching staffs (based on ERA).

Overall, Chicago's opponents through Tuesday had a combined ERA of 4.86. You could argue that part of the reason that number is so high is because those teams had to face the heavy-hitting Cubs -- but that doesn't really hold much water, given that only Cincy played Chicago more than three times. Meanwhile, Washington's foes have a combined ERA of 4.04. That's a pretty big difference.

So maybe the Cubs' offense isn't quite as good as we've been led to believe over these first few weeks. That said, Chicago is averaging 6.12 runs per game, almost 50 percent more than Washington (4.12). Oh, and there's this: Through Tuesday, the Cubs' on-base percentage was .362, which was only five points lower than Bryce Harper's .367.

Nats leadoff man Ben Revere -- who has been out since Opening Day with an oblique injury and is expected to return against the Cubs -- should help ignite the Washington offense, but not enough to give it the edge over Chicago's lumber-laden lineup.

Advantage: Cubs

DEFENSE

Daniel Murphy has been a boon to D.C.'s D and Jason Heyward has lived up to his Gold Glove credentials in Chicago. Getty Images, Icon Sportswire

The Nationals weren't expected to be an exceptional fielding team, but their nine errors so far are the fewest in the majors, and their .991 fielding percentage is the best. Harper and Daniel Murphy -- yes, the same Daniel Murphy whose glove flub cost the Mets Game 4 of the World Series -- lead the way in defensive runs saved, but as a team, advanced metrics don't love Washington, whose minus-3 DRS ranks 10th in the NL.

In other words, the Nats have been catching what's hit their way, but not a whole lot else.

Facing a Cubs squad that has swiped 17 bases (tied for third in the NL), Wilson Ramos could be an X factor. Last season, Washington's backstop gunned down 44 percent of opposing baserunners, best in baseball. He's at 40 percent this season and his arm should be fresh after missing a week on bereavement leave.

As for the Cubs, three-time Gold Glove winner Heyward (4 DRS) leads a defense whose 13 runs saved are the most in the NL. However, Chicago has committed 15 errors. Behind the plate, Cubs catchers have combined to throw out just 23 percent of opposing runners and have allowed 20 steals, third most in the NL. With the return of Revere -- who swiped 30-plus bags in four of the past five seasons -- that could be a problem.

Advantage: Even

STARTING ROTATION

Jake Arrieta is the best pitcher in the galaxy, but Max Scherzer and Stephen Strasburg pack quite a one-two punch. AP Photo, USA TODAY Sports

Trying to decide who has the better rotation is kind of like trying to decide between a burger from Five Guys or Shake Shack -- they're both ridiculously good. In fact, at this very moment, the Nats and Cubs both have a starter ERA of 2.19, which is more than a half-run better than the next-closest team in the bigs.

Jake Arrieta is the best pitcher on either staff, not to mention either planet (Earth or Venus). After that, I'll take Washington's dynamic duo -- Max Scherzer and Stephen Strasburg -- over Chicago's Jon Lester, who's off to a great start (1.58 ERA, 1.05 WHIP) but isn't quite on the same level.

What really makes both these rotations special is their depth. Washington's Gio Gonzalez has a shiny 1.15 ERA that's second best in the NL. Tanner Roark, who recently tallied 15 K's in a game and is supposed to be the Nats' No. 4 starter, ranks ninth with a 2.35 ERA. Then there's 22-year-old Joe Ross, the former first-rounder whose 0.79 ERA is the best on the staff, but who isn't among the league leaders because he missed a start and a half with a blister and therefore doesn't have enough innings to qualify.

For Chicago, Jason Hammel's 1.24 ERA ranks third in the NL, right behind Gonzalez. Lackey might not be off to the best start judging by traditional metrics (4.32 ERA), but his 3.30 FIP (fielding independent pitching) is just a hair higher than Lester's and suggests that he deserves better. Then there's No. 5 starter Kyle Hendricks, whose 4.75 K/BB ratio would be top 10 in the NL if he had a couple more innings.

Advantage: Nationals (but just barely)

BULLPEN

Hector Rondon has been unhittable. Jonathan Papelbon, on the other hand ... Icon Sportswire, Getty Images

Despite neither team having a bullpen filled with blue-chip hurlers, Chicago and Washington rank 1-2 in the NL in reliever ERA (2.66 and 2.69). But the Cubs' pen allows fewer baserunners (an NL-low 0.99 WHIP), misses more bats (an NL-high 11 K/9), and is way better at stranding opponents (only 14 percent of inherited runners score, best in the NL).

What's more, the guys at the back end of these two bullpens appear to be headed in opposite directions. Washington closer Jonathan Papelbon blew a two-run lead in Tuesday's loss to the Royals and opposing batters are hitting .320 against him. His K rate, which has never been lower than eight per nine innings, is down to 6.8, and his average fastball velocity is 90.8 mph, down from 94.8 in 2011.

As hittable as Papelbon has looked, that's how unhittable Hector Rondon has been. In his third season as Chicago's closer, the 28-year-old righty has allowed just four hits in nine innings, while striking out 15 and walking zero. If you're keeping score at home, that's a K/BB ratio of infinity. Opponents are hitting just .133 against him and his high-90s cheese.

Advantage: Cubs

MANAGER

Dusty Baker versus Joe Maddon? Take your pick. Getty Images

Between them, Dusty Baker and Joe Maddon have more than 2,500 regular-season wins, five Manager of the Year awards and 12 playoff appearances. Not to mention lots of fans: Those who know them speak glowingly of both. Those who don't tend to take a shine shortly after meeting them. They've both spent 60-plus years on this planet and have a knack for making those around them feel comfortable.

So who's the better bench boss? That's like asking what hand Lefty Grove threw with -- there is no right answer.

Instead, we'll let the facts do the talking, and the facts say this: Despite nearly 5,000 games managed between the two of them, if the Nationals are able to take three out of four in Chicago this weekend, Baker and Maddon will have the same exact .528 winning percentage.

Advantage: Even