Funny thing is everyone at Woodstock will tell you they were tripping balls off and played lousy sets. Took 2 hours to get Hendrix coherent enough to bring him to the stage. John Sebastian will admit it. Santana was tripping so hard all they saw was hair and teeth and turned their backs to the horde out there.
IMHO there were really only two good performances at Woodstock, Ten Years After, and Sly and the Family Stone.