Savo Island was a bad defeat, but the Japanese withdrew, forfeiting an opportunity to destroy American transports supplying the new landings at Guadalcanal.
Tassafaronga was another defeat, but again the Japanese withdrew without unloading supplies badly needed by their starving army on Guadalcanal.
As to the Civil War battles, it depends on which Americans you're cheering for as to whether it was a victory or defeat. Several other battles had a much bigger effect on the outcome of the War.
Gettysburg was the CSA defeat that sealed their fate.
Crushing rout.
the list is forgotten battles, most remember Pearl