bad head?

yesterday i agreed to give a friend head, it was planned ahead and we had planned to do it in his car. i was confident because i’ve been told by both of the other sexual partners that i’ve had (2) that i give amazing head (and i feel that i do a good job too.) but to sum up the story i gave him head but it took him AN HOUR and a half to come. any other time i have given head it has only taken 2-10 minutes. this terrible experience has just lowered my self-confidence about the topic and embarrasses me. i’d also like to add that his penis was definitely on the small side.. i understand that all men are different but could this be my fault ?