Really? Here's the excerpt from the novel, right at the point when Palps was firing lightning at Mace and had him in trouble.
Pg. 334 of the hardcover Revenge of the Sith novelization:
If you will notice, Palpatine was on the brink of destroying Mace, but with Mace pleading with Anakin for help, Palpatine figured Anakin might side with Mace so he goes DIRECTLY from dominating Mace to the point Mace says "Anakin, he's too strong for me...", to becoming that feeble old man.
So Nurb, I'd say the novelization does make it quite obvious that Palpatine "gave up" in his fight because he didn't want to risk having Anakin side with Mace at that moment. That excerpt, atleast, definitely points to it.
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Actually it is a stalemate. Neither of them is able to take advantage at this moment. When Ani cut off Mace's hand and he loses lightsaber then Palps uses lighning to finish him (Windu was a swordsman and hadn't big experience with force absorption like yoda so without lightsaber he was defenseless)