Just how good is this Red Sox offense?

What on Earth is happening?

The Red Sox continued on Wednesday night to make a mockery of preseason expectations that their offense might struggle to produce runs by scoring 13 or more runs for the third straight game. A 13-3 victory over the A’s concluded one of the most lopsided series sweeps in recent memory.

“It was certainly embarrassing,” A’s outfielder Josh Reddick told reporters after the three-game set that featured a combined 40-15 Boston advantage.

The trio of contests marked the first time in Red Sox franchise history and just the seventh time in the last 100 years (and the first since 1999) that any team had cooked up a baker’s dozen of runs in three straight contests. The offensive numbers are reaching the point of early-season absurdity. A few markers:

■ The Sox are averaging 5.76 runs per game – more than a full run per game ahead of the second-highest scoring team in the AL (Texas, 4.74).

■ The Sox have five players (Xander Bogaerts, Travis Shaw, David Ortiz, Jackie Bradley Jr., and Dustin Pedroia) hitting .300 or better; no other AL team has more than two.

■ The Sox have 86 doubles, on pace for 410 this year. The major league record for a season is 376.

■ The Sox have homered in 12 straight games, tied for their longest streak since 2007, when they had a 13-game run.

■ In every spot of the order except the leadoff spot, the Red Sox’ OPS ranks in the American League’s top five – a suggestion of a relentless lineup that permits opposing pitchers no chance to catch their breath. The Sox lead the AL in OPS from the fourth, seventh, and ninth spots – gaining a particularly gaping advantage from the last spot in the order thanks to Bradley’s demolition show.

The Sox have received an .899 OPS from the ninth spot – more than 120 points better than the second place team (A’s, .773) and more than 350 points better than the third-place team (Blue Jays, .643).

In essence, through a fifth of the season, he’s resurrected the advantage that the 2003 Red Sox had when Bill Mueller won a batting title from the bottom of the order.

Those are the outcomes – the runs, the hits, etc. So what are the numbers behind the numbers that help to define the Red Sox’ offense?

■ The Red Sox enjoy home cooking – or, more accurately, hosting barbecues in which they put opposing pitching staffs on the grill. They’re averaging 6.6 runs per game at home.

■ The Red Sox put the ball in play. They have punched out in 19.9 percent of plate appearances this year, the 11th lowest mark in the big leagues (one spot behind the renowned kings of contact, the Royals), while they are middle-of-the-pack in terms of their walk rate (8.1 percent, 18th in the majors and 10th in the AL).

■ They are, as assistant hitting coach Victor Rodriguez likes to say, using the big part of the field. The Sox have 83 opposite-field hits this year, 18 more (28 percent) than any other AL team; they have 36 opposite-field extra-base hits, 15 more (71 percent) than any other AL team.

■ They do damage in all counts. The Sox are easily the best team in the AL with two strikes, posting a .227/.287/.348 line when down to a final strike, with a .635 OPS that is more than 130 points better than league average. They’re also second in the AL in hits with no strikes (96). Pitchers can neither ease into a count nor can they feel comfortable when they are ahead.

■ They’re enjoying a measure of good fortune. They have a .344 batting average on balls in play, tops in the majors. Even though, as Matt Collins wrote for Over The Monster, there are reasons to believe that the Sox can maintain a well above-average BABIP, that extreme number probably is not sustainable, given that the highest mark in the last 100 years is .331.

■ They keep the pedal down on the bases. The Sox are second in the AL with 42 bases taken on fly ball outs, wild pitches, passed balls, balks, and defensive indifference; they’ve scored from first on doubles in 17 of 30 opportunities this year, a 57 percent rate that is tops in the AL; they are second in the AL with 27 steals, yet have been thrown out just twice, good for a 93 percent success rate. No other team enjoys as much as an 80 percent success rate.

It’s been a brilliant run, of course – a 14-5 stretch that vaulted the Red Sox from a 7-8 drift into mediocrity to a 21-13 mark that is tied for first in the American League East. But it’s still a bit premature to declare this team the second coming of the 2003 edition.

Of those 19 games, 16 have come against the Astros (3), Braves (4), Yankees (6), and A’s (3). All four currently reside in last place in their respective divisions, with winning percentages of .406 or worse. The Sox did lend an air of credibility to their stretch by taking two of three in Chicago, but by and large, the Sox have feasted on wounded prey.

Aside from White Sox lefthander Jose Quintana, the Sox have faced a far from decorated group of pitchers. The 17 starters whom the Sox have faced during their current run (they faced Yankees Michael Pineda and Nathan Eovaldi twice each) have a combined ERA of 4.76 – a mark that, among the 102 starters who qualify for the ERA title, would fall between the pitchers who sit at No. 79 (Jered Weaver, 4.72) and No. 80 (Eovaldi, 4.78) on the list.

Nonetheless, the schedule is certainly no fault of the Sox’, and to date, they’ve done more against less than any other team in the American League.

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