Derrick Henry had arguably the greatest run in NFL history Thursday night ... and his pal Mark Ingram couldn't have been prouder -- 'cause he lost his mind watching it!!!
ICYMI ... Henry tied the longest run ever in the NFL with a 99-yard TD in the 2nd quarter of the Titans' blowout win over the Jags -- and the play was epic.
Derrick stiff-armed three dudes, tight-roped the sideline and outran the entire Jacksonville defense to tie Tony Dorsett's longest-ever TD run.
Ingram -- who won a Heisman Trophy at Alabama just like Henry -- went bananas watching the replay .