Hi Mohammed ..
First, congrats for the draw 
Second, you were very lucky that your opponent made such a terrible blunders, it look like he is underestimated the end game position, but be carful when you play against stronger players they don't make such mistakes 
Anyway, your opponent was having mate in 3 moves :
Hi, one tell me " why you resign quickly, maybe your openent make a mistake " so thanks very thanks for this advice ! :)