He stole a car from outside a house in Radley earlier this year.
Robert Zasada burgled a property in Stonhouse Crescent at about 2am on 18 February.
The 28-year-old, who doesn't have a fixed address, made off with a Volkswagen from outside the property.
Later that morning Zasada lost control of the car and collided with a tree and lamppost in Radley Road.
Officers attended the scene and one of them was assaulted by Zasada.
Investigating officer, Detective Constable Dan Tibble of South and Vale Area CID said: "While in police custody, Zasada then failed to provide a specimen of breath.
"All too often Police officers and staff who work on the frontline enforcing the law are assaulted and this case highlights this serious issue.
"I am pleased that Zasada has been convicted and will be sentenced in due course."
Zasada pleaded guilty to one count of burglary, one count of aggravated vehicle taking, one count of driving without insurance, one count of driving without licence, one count of failing to provide a specimen of breath and one count of assault by beating of an emergency worker at Hove Trial Centre Crown Court on Thursday (8/8).
He's due to be sentenced at Oxford Crown Court on 2 September.