This player is a cheater. I experienced first hand his dirty playing.
When he is unsure to win, he make a connection problems with all the opposite teams and the weakest ping of that team will drop. It will appear like a simple deconnection for most, but it isn't. The connection page did pop up and it clearly shows (even for a few sec) that he and all of my team had connection problems. Strangely, no other dropped or have any other issues, and no lag for that matters.. After the player dropped, he farmed the comp when possible.
Proof? Most of his wins against good players are from games that one opponent dropped. Records are on his gamelist page.
End of line: Do Not play with this cheater, or face the consequences. You have been warned.