First, his defense was a good counter for your offense. 1-3-1 vs Motion. This gave him more blocks and steals than your team had, which lead to more opportunities for him to score. 22 more shots for his team and 10 more makes.
I'm sorry, I read it backwards. You are correct, it is a good counter to stop the outside shot, although 3-2 may be better so that you have someone back to rebound with.
That would explain the difference in offensive rebounds.
Your PF got outplayed as well. He turned it over 6 times and fouled out of the game. His PF also had 3 blocks, so that might be a weakness too.
With the 1-3-1, his Center was on an island and stepped up to the challenge.
This should say that your Center was on an island and it showed in the stats.
Yeah, looking at it again, offense was stymied by defense in both cases, but the turnovers (blocks and steals) and offensive rebounds are what won the game for him.