One startling fact jumps out of the Yankees-Nats series last weekend. The first four hitters in the New York order saw 301 pitches in the three-game series while the first four hitters in the Nationals order saw just 181, a gap of 66 percent. The Yanks were off-the-charts patient; the Nats were incredibly over-eager.

This borders on amazing because the hitters who were used in those top four spots in this series are — normally — indistinguishable in selectivity. Collectively, the Yankees’ and Nationals’ top-of-the-order hitters are close to the MLB average of 3.82 pitches-per-at-bat. Only Curtis Granderson (4.29) and Adam LaRoche (4.17) are especially picky, and only Robinson Cano (3.46) and Steve Lombardozzi (3.40) are free-swingers. Everyone else used in those first through fourth spots (10 players total) falls between 3.75 and 3.92.

Yet last weekend, both teams diverged to a huge degree from their normal patterns. The Yanks’ first four hitters averaged 4.49 pitches per at-bat, which is astronomical. Only one player in MLB this season (Adam Dunn) is seeing more than 4.35 pitches-per-at-bat.

The Nats averaged just 3.18 pitches-per-at-bat, as if they all started swinging while still in the on-deck circle. That’s well below Delmon Young’s lowest-in-the-majors average of 3.28 pitches per at-bat.

In other words, the Yanks entered Washington with extra veteran patience while the Nats were itchy in the hometown spotlight.

Also, the Nats pitchers likely showed the big names at the top of the New York order even more respect than they deserved. Those four Yanks hit just .237 in the series but drew walks and got Nat starters out of games with high pitch counts.

At the plate, the worst Nats offender was Ryan Zimmerman (1-for-14), who averaged just 2.93 pitches per at-bat, far below his 3.93 career average.

For what it’s worth, the teams’ fifth through ninth hitters saw almost identical numbers of pitches per at-bat. The disparity was at the top of the order, where the best hitters, usually selective, supposedly live.

Was this a unique case of stage fright for the Nats hitters, nibbling timidity by Nat pitches and a red-hot confident Yankee team?

Well, the previous weekend in a much-watched series against the Red Sox in Boston, there was no such pattern. The first four hitters in the Boston order — including smart batters such as Dustin Pedroia, David Ortiz and Adrian Gonzalez — saw a total of 217 pitches. The Nats top four hitters saw 216.

To summarize this large difference from one weekend sweep to the next, look at pitch counts to the top four hitters in each batting order: 301-to-181 in Washington versus 217-216 in Boston.