I recently got disconnected from a 1v1 quick match. I checked my match history and this game was never recorded. I was under the assumption that disconnects were counted as a loss. However, this doesn't seem to be the case.
How are disconnects handled?
Update #1
I remembered my opponents name and looked up their match history on sc2ranks.com. I was able to confirm that a win was recorded for them. However, the match is still missing from my match history after nearly 24 hours and my w/l has remained the same.
Update #2
The match history is still missing after two days and I'm going to assume that it will remain missing. Do note that my opponent was awarded a win. This is either a bug or a decision the system made due to some unknown reasoning.
In the majority of cases, it should be understood that a disconnect is counted as a loss.
Best Answer
Disconnecting means you lost the match.
But as @Juan commented, they don't appear on your match history instantaneously, so it may take some time to show up. Especially because your Battle.Net account didn't receive the end result directly after the match was ended, so it needs to look up what happened.