The Sox accomplished this feat largely with the following pitchers either injured or demoted, I think that is an underappreciated aspect of this:
Crochet
Ovieto
Suarez
Early
Bello*
On the hitting, the Sox OPS the last 30 days is 0.759. For the season it is 0.707. Sure, they have been hitting better (Yoshida, Durbin in particular), but this is not making the difference between 32-46 and 19-3. There is some element of chance or luck in this. It is how baseball works. Some balls are hit hard right at someone, some find their way to hits. And sometimes the hits happen with men on base, sometimes with 2 outs and nobody on. This applies to the Sox and the other team.
Nearly everything went right for 21 games. A statistical abnormality or outlier. The team did play better, but not this much better. The team is not as bad as they seemed at the start and of course, not 21-3 good either. Probably more like 90 win good or better, at least with Crochet healthy.
I think it is good they have the day off today. They can catch their breath, regroup a little. They now have 61 games to determine what kind of team this really is. Back to the grind.