Exactly, especially qualifies who Jesus is a Saviour to, believers, the sheep or those who had been ordained to eternal life Acts13:48
Not to mention that John 3:16 specifically teaches the exact same thing, for anyone who would bother to read it:
John 3:16 “For God so loved the world, that he gave his only Son, that whoever believes in him should not perish but have eternal life.
Summarizing, "God gives believers eternal life BECAUSE He loves "the world" in this particular way.
So if you make "world" and "believers" refer to two different groups, you make nonsense of the passage.