Tyreek Hill's letting his detainment fuel his competitive fire ... putting his hands behind his back after scoring his 80-yard touchdown during Sunday's game.
The wide receiver -- who was detained by police just hours before his Week 1 matchup against the Jacksonville Jaguars -- just scored a huge TD ... and, fans filmed his reaction in the endzone.
After scoring, Tyreek turned toward the crowd and put his hands behind his back .