Odell Beckham Jr. -- BLOWS DIDDY AWAY ... In Street Footrace

Here's video of NFL superstar Odell Beckham Jr. -- proving he's WAYYYYY faster than non-NFL superstar Diddy.

OB2 was in West Hollywood yesterday -- where he decided to test his foot speed on the same steep hill where Diddy was running sprints back in February.

According to our unofficial clock ... Beckham ran the hill a full 2 SECONDS faster than Diddy did it.

So, congratulations Odell ... you're faster than a 45-year-old non-professional athlete.