Meaning of おめでとさん


During a boxing match a spectator is congratulating a boxer for winning the
previous match saying this sentence:

> ２回戦突破おめでとさん

What is the meaning of おめでとさん? He his clearly congratulating the guy, so I
think it must come from おめでとう, but why the omission of the う and the addition
of さん? I don't think it could really be the guy's name.

[Here you can see the whole page where it is taken
from.](https://i.stack.imgur.com/QBABy.jpg) Thank you for your help!




It's one of ways to say おめでとう more friendlily. The closest translation would
be congrats?  
There're similar type of words like ごくろうさん, おつかれさん, and ありがとさん.




It's one of ways to say おめでとう more friendlily. The closest translation would
be congrats?  
There're similar type of words like ごくろうさん, おつかれさん, and ありがとさん.

