I remember that story. It's of my favorites. I read with my 8 year old again a few months ago. Vandal had them traveling through time and it ended up in a hand to hand fight with Supes using energy he was leeching from Power Girl ( the real Power Girl not the confused present inposter.)
Got that right, SteamTeck.
Not only was Savage cheating by using Power Girl to power himself, but the planet he set up the fight on had a
kryptonite sun which was depowering and killing Superman. Vandal took every advantage he could. If the JSA hadn't freed Power Girl and Star-Spangled Kid hadn't whipped up a protective suit from the K-radiation, Kal-L would've been soundly defeated and dead.