I'd say thats the one glaring flaw for Spence right now and brook never took advantage. But when his opponent throws combos he just puts his hands up until they're finished. he does respond back quickly. But still, vs a good combination puncher he could have problems. But I don't think any of them dudes at 147 are great with combos. And none of them will be able to back Spence up. Hes simply too big, too physical, and too sharp for the remaining guys at 147. His defensive flaws won't be a danger for him until he moves up to 154.