It's guess that even for Trump there's probably a fine balance between:

• wanting to be seen as a 'winner' by associating yourself to 'winners'; and
• disdain for critics that tarnish your personal image, since that would make you be seen as a 'loser'.

And I'd pretty sure Obama making a joke about Trump hijacked the later in Trump's mind.

Being more realistic through, is that this winners/losers is really an observable tendency in Trumps' decision making process, however the fact is that it's obviously not a binary decision and there's nuance to It, since the human mind is usually not 'rational', not immutable, and also not necessarily consistent, in its decision making process, over time.