Your question stems from a misunderstanding. Lily Potter's sacrifice of her own life (in order to defend her infant son, Harry) is what created the magical counter-curse. Had his mother been a muggle, her sacrifice would not have created the sacrificial protection charm and he would have been at the mercy of Voldemort who sought to kill him in order to stymie the prophecy.
In a 2005 interview, JKR makes it clear that the protection stems from his mother, rather than simply having been conferred by the circumstances;
JK Rowling: That has been explained in the books to an extent, it has been explained in the books but possibly you haven't yet finished
this book when it is made very clear. Harry receives magical
protection from his mother's sacrifice as long as he remains close to
her blood. In other words, Aunt Petunia. That protection won't
continue to hold once he is a man, once he turns 17 - he is no longer
given that protective aura by his mother, so Dumbledore wants him to go back one more time to ensure the protection continues to his
17th birthday and after that he really is on his own.
For the record, Harry himself was (as has been discussed) largely average as a wizard and certainly no match for Lord Voldemort. His mother, by comparison is described as having been "talented", "skilful", "bright", etc etc.
Your mother died to save you. If there is one thing Voldemort cannot
understand, it is love. He didn't realise that love as powerful as
your mother's for you leaves its own mark. Not a scar, no visible
sign... to have been loved so deeply, even though the person who loved
us is gone, will give us some protection forever - Harry Potter and the Philosopher's Stone
"But I knew too where Voldemort was weak. And so I made my decision.
You would be protected by an ancient magic of which he knows, which he
despises, and which he has always, therefore, underestimated — to his
cost. I am speaking, of course, of the fact that your mother died to
save you. She gave you a lingering protection he never expected, a
protection that flows in your veins to this day." - Harry Potter and the Order of the Phoenix