I disagree
Anway he definitley didn't "decimating" them
It's not about disagreeing, it's about facts.
Chapter 990
ALL the panels in which Sicilian&co are shown they are beating gifters and Number, no mink is shown taking hits. The only one who is sending them flying around is Jack, at this point the Dukes came in.
Chapter 991
Jack is defeated by the Dukes and all the minks are shown exhausted on the ground (Sicilian too who is the leader and was shown in 991 slaying one gifter after the other).
The only one who reduced them in those conditions is Jack, possibly with some help by Nagi