By TMZ Sports

Former world champion Zab Judah tried to lie after a Las Vegas car crash back in January -- claiming his name was "Michael Johnson" ... and the whole thing was caught on video.

The 38-year-old boxer allegedly smashed into another car at 7 AM on January 29th -- and the victim pulled out her phone to document the aftermath.

You can see Judah -- a former 4 time world champ -- in the driver's seat ... slurring his words as he's confronted by the other driver.

When the woman asks for his name, Judah says, "Michael Johnson."

The woman told Judah he "smacked the s*** out of me" and was responsible for the damage and her injuries.

She also told Judah she was calling the police because it was "obvious" he had been drinking. However, we've done some digging and can't find a record of Judah being arrested for DUI on that date.

Sources connected to the incident tell us Judah's insurance company settled with the woman ... and it was only then that the woman learned Judah's true identity.

We reached out to Judah's camp for comment. So far, no word back.