How do we know that death has no mastery over Christ? Romans 6:9 says:


  For we know that since Christ was raised from the dead, he cannot die again; death no longer has mastery over him.


The logic here says that since Christ died and was risen, now he cannot die again.

With that same logic, we might say that Lazarus (who died and was risen) or anyone else who was raised from the dead - that death has no mastery over them either. 

Obviously Christ is the son of God, so that makes him different, but Paul is making a specific argument here. Why is Paul's argument true for Christ but not for Lazarus?
Lazarus and others died of the "first death" and were raised back to the same earthly body as before they died. Their ultimate fate was still to be determined, be it everlasting life or the "second death" on judgement day. 

Jesus died of the "second death" to pay the penalty of death for believers. He was raised up in full glory as a conquerer, and it is through Him that we have hope in the same eternal resurrection. 

On a deeper note, death never had mastery over Jesus per se, except that He allowed it willingly to pay our debt. Jesus says, 


  "I have the power to lay it down, and I have the power to take it again" (John 10:18)