Progress? Or Just A Lucky Night?

Today Danny fell asleep by himself again! It happened just a couple times before... like 2 and yesterday - but he cried on and off and complained and I had to go back to him like 3 times and try to rock him so I just thought he got tired and fell asleep. But today Danny woke up 15 minutes after I breasfed him and put him down sleepy (not asleep) into his crib. I tried to pick him up and calm him down but he would just cry in my arms which I cannot stand... after a 5 minute battle I just put him down and decided to give him 5 minutes to cry... after 3 minutes crying subsided and after 4 minutes I didn't hear anything... I even got worried he is unwell so I went to check on him. But he was perfectly fine - lying on his side and falling asleep... Amazing! I wonder if this is definite progress or just tonight...