Blast vs Invincible

Blast, due to his porphura DNA, is weaker, slower, and less durable than Invincible. Mark also has a higher Pain Tolerance, as Blast isn't as used to be hurt and taking heavy damage. Blast's regeneration gives him an advantage, unless his Heart or Brain are severely damaged. His regeneration drains his Stamina, but he has higher stamina than the average Viltrumite, so it's not a huge weakness. Blast, due to his profession as a Bounty Hunter, is far more likely and willing to go for the kill than Mark. His Rage Mode also gives him strength and speed comparible to Mark (and even greater as it continuously increases in that primal state), at the cost of him going berserk and fighting like an animal. Blast has more experience and skill as he's been training as a Bounty Hunter his whole life, whereas Mark only started at 17.

I believe Mark could win despite the advantages that Blast has, due to him using his powers more creatively, and because Blast needs his risky Rage Mode to match any of Invincible's physical abilities. Even then his durability doesn't increase, so Mark can still land heavy damage. I think Blast's stamina will give out from fighting and constantly regenerating before he manages to defeat Invincible.