In interleague, they’re beyond compare

And then, the Red Sox finally can stop beating up on the little kids and return to the American League, even if it’s against the worst team in their division, the Baltimore Orioles.

Interleague play is in full bloom in this 2009 season, and the results so far have been exactly as anticipated. The Red Sox are wiping the floor with the National League. Boston had outscored the Marlins by a 14-3 count entering last night’s series finale.

With Wednesday night’s 6-1 win behind Brad Penny, the Sox were 5-3 in interleague play this season. Since the start of the 2003 campaign, Boston is 76-40 in regular-season games against the other league, tied with the Minnesota Twins for the best record in baseball.

The Red Sox vs. the National League is baseball’s version of Godzilla meets Bambi, akin to watching a home winemaker stomp on a batch of grapes.

Here are five reasons the Red Sox rule baseball’s other world, starting with the most obvious.

1. The National League stinks.

Fine, so the Philadelphia Phillies won the World Series last year. Big deal. Entering last night, the American League had a .521 winning percentage against the National League this season. Since the start of the 2003 season - the year that coincides with the start of the Red Sox’ dominance - the AL winning percentage was .542. And since the start of the 2006 campaign, the AL had a whopping .579 winning percentage, which translates into a 94-68 record over a 162-game schedule.

Know what that means? It means that over the last three-plus seasons, if AL teams played exclusively NL teams, the AL teams would go an average of 94-68 while the NL teams would go an average of 68-94. Pennant races would be over by July 1. Send in the clowns.

Having already played the Mets and Phillies - their only two interleague opponents with winning records - the Red Sox look to have an easy schedule in the coming days, even without the use of a designated hitter in National League parks.

And while the Mets did take two of three from the Sox at Fenway Park last month, there is evidence to suggest that the series outcome was something of an aberration. One of New York’s wins in that series came on a blown save by Jonathan Papelbon, the only time this season the Red Sox have lost a game they had led after six innings. In those situations, the Sox are 33-1.

2. Scouting.

As much as any team in baseball, the Red Sox are proficient at breaking down opponents and exploiting weaknesses. This was never more apparent than during the 2004 and 2007 World Series, both of which resulted in sweeps. (Yes, those were interleague games.)

In those contests, the Red Sox went 8-0 while posting an aggregate 2.50 ERA against the St. Louis Cardinals (2004) and Colorado Rockies (2007), who hit a combined .205 against Boston.

It is one thing to identify an opponent’s deficiencies, another to exploit them. The latter speaks to execution, which is a reflection of the players and their talents.

Nonetheless, the Red Sox of today are as thorough as any team in baseball when it comes to melding philosophies of the old school and new school - traditional scouting with sabermetrics - and their advance scouts, in particular, know how to evaluate opponents.

The ultimate point is that the Red Sox are prepared, from the front office to the man squatting behind the plate. They generally have all their bases covered, which is especially important when facing teams you may see once every few years.

3. Fenway Park

Sooner or later, doesn’t it always come back to the ballpark?

During the Theo Epstein era - that is, beginning with the 2003 season - the Red Sox have the best home record in baseball (341-178) and have scored more runs at home (3,082, an average of 5.9 per game) than any other team in the game. The Red Sox effectively have built their team to fit their ballpark, and the numbers prove it.

Against the National League, those numbers are even better. With Wednesday night’s win, the Red Sox were a major league-best 43-16 in interleague home games since the start of the 2003 season, a .729 winning percentage that translates into 118 wins over the course of a 162-game schedule. (Now that’s dominating.)

During that span, the Sox have outscored opponents by 133 runs, an average of roughly 2.3 per game.

But wait, there’s more. During those 59 games, the Red Sox have batted .312 with a .388 on-base percentage and .512 slugging percentage. That’s an OPS of .900. In interleague games over the past six years, that is sort of like sending Hanley Ramirez or Ryan Howard to the plate - for every at-bat.

4. Depth and versatility

When you look back, the funny thing is that the Red Sox were once atrocious in interleague play. From 1997-2002, a period that essentially encompassed the entire Boston managerial career of Jimy Williams, the Sox went 45-58 in interleague games, a .437 winning percentage that was seventh-worst in baseball and third-worst among AL clubs. When the National League teams showed up, the Red Sox got exposed.

While some of that had to do with the fact that the NL was a better league then - even if only slightly better - the greater problems concerned the one-dimensional nature of those Red Sox. Back then, the Sox were not the deep offensive club they are now. Losing the designated hitter hurt them badly. The Sox similarly lacked speed, making scoring even more difficult.

Indeed, from 1997-2002, the Sox went 25-28 in interleague home games, but a brutal 20-30 on the road. They scored fewer runs (201, an average of 4.0 per game) in NL parks than all but six clubs.

When the Red Sox travel to the NL now, they have a deeper lineup - with or without David Ortiz - more speed, and generally play better defense. Since the start of the 2003 season, their interleague road record of 33-24 is third-best in baseball.

5. The lineup

The Red Sox simply are not easy to pitch to. This year’s lineup doesn’t have the same kind of punch that previous Sox clubs had, but by comparison, they still dwarf most anything in the National League. The Red Sox rank fourth in the American League in runs, but they have outscored the Phillies, who lead the NL.

When pitchers like Andrew Miller (Wednesday) and Chris Volstad (Tuesday) take the mound against the Red Sox, they are seeing lineups they are not accustomed to seeing. Since the start of the 2003 season, NL teams have a 5.89 ERA against the Red Sox. Toss in the two World Series blowouts and the number actually climbs to 5.95.

Even the best teams in the NL have not been able to negotiate their way through the Boston batting order. Just ask those 2004 Cardinals and 2007 Rockies.

Tony Massarotti can be reached at tmassarotti@globe.com and can be read at www.boston.com/massarotti