Demetrious Johnson knew he'd made the right decision ... advice from veterans and fellow retired UFC fighters Georges St-Pierre and Khabib Nurmagomedov confirmed he had made the correct choice.

Demetrious Johnson (middle) shares the advice that was given by Georges St-Pierre (left) and Khabib Nurmagomedov (right) before his retirement [Images courtesy: Getty Images] Being an MMA veteran ...