The guy who jacked Venus Williams' Fiat 500 was quick to confess when cops pulled him over Saturday in L.A. ... but he then played a very short game of catch me if you can.
Car thief Gabriel Vella ran a red light near the Staples Center ... which caught the attention of the men in blue.
An officer approached the vehicle and Vella instantly copped to driving a car he had stolen from a West L.A. neighborhood -- so he was promptly cuffed and placed on the curb.
That's when Gabriel stood up ... AND BOLTED!!
The officer chased him down, backup arrived and Vella was cornered in an alley a few blocks away.
Here's the weird part of the story. According to the police report, Venus never reported the car stolen.
Thieves with big mouths get caught.