Woods hit the course yesterday with two male companions and practiced his ass off from 8:30 AM to 5:00 PM -- working on everything from drives to pitches and putts.
We're told Tiger's session was uninterrupted -- and he seemed completely focused throughout the entire grueling workout.
As we previously reported, sources in Isleworth tell us Tiger is dead set on competing for the Tavistock Cup -- which will be held at the same Isleworth golf course where he's practicing.
And with that news ... Phil Mickelson probably needs a fresh pair of undies.
