WRITTEN BY RIYA DUBEY
Gohan is Goku's elder son and is one of the strongest fighters in the 'Dragon Ball' series. He is a half-Saiyan and they are much more powerful than full Saiyans.
Jiren is one of the most difficult opponents Goku ever had to face in the series. Jiren is a warrior from universe 10 and is their strongest fighter. He is even stronger than the god of destruction of the universe 10.
In a full-fledged battle, it is hard to determine who would win. Gohan is extremely powerful, but Jiren is not easy to defeat either.
As fans know, Gohan stopped training with his father and as a result, has grown weaker. Whilst his Beast Gohan form is one of the strongest in the series, it is still weaker than Jiren.
Jiren on the other hand is as strong as he can probably get. He managed to hold off Ultra Instinct Goku and it took the combined efforts of universe 7 warriors to finally defeat him.
This entails that the current Beast Gohan would not be able to defeat Jiren as the form is not stronger than Ultra Instinct.
It does not mean that Gohan is inherently weaker than Jiren. At the peak of his power, Beast Gohan would be able to defeat Jiren.
Whilst, the current Beast Gohan would not be able to defeat Jiren, he has the potential to defeat him.