Boxing star Otto Wallin says if Tyson Fury vs. Deontay Wilder III ain’t happening, he’ll step in and rematch the Gypsy King … ’cause he already whooped him once!! The HIGHLY anticipated trilogy fight was *supposed* to go down this year, but Fury says Wilder keeps changing the date … so TF’s moving on. But fear not, Fury fanatics — 29-year-old Wallin says he’s been training like a maniac … and he tells TMZ Sports he’s more than ready. “He doesn’t have to look any further,” Wallin tells us. “To be fair, look at our fight and then look at his other fights.” “You can see that I did a much better job than anybody has, and I landed more punches than (Wladimir) Klitschko and Wilder even together.”