Some matches are really suspicious, but you can't say he expected to beat Godović at USopen.
This one is the most disgusting:
Eastbourne 2011: F Andreas Seppi L 6-7(5), 6-3, 3-5 RET.
Retiring one game before Seppi winning his 1st title and spoiling his joy.
Perhaps he just hates losing and when feeling bad or slighly injured it's his way to say "you aren't really better than me, I'm not feeling well, so I'll just retire".