During WWHulk Dr. Strange visited Banners mind and had his Astral hands broken, which resulted in Strange taking the same damage in physical space.
If Despero's power works in a similar manner, I see him failing as well to take over the Hulks mind, or body.
If he attempts to take over his mind in ways that mirror Xavier's, I see him suffering from a similar psychic backlash that pushed Xavier and Emma Frost out of his mind as well.
In my opinion this would end is a physical confrontation, and I don't think that Despero can hang with the Hulk for very long. So far the Hulk's strength can not be measured.
The Hulk's healing factor eliminates lactic acid from impairing the Hulk, so he could virtually fight non-stop for weeks on end, and only because of the fact that he needs to eat.
My vote is on the Hulk breaking something within Despero, after a long fight, and ultimately winning.