The fight with Huan I'll give you.
Sauron versus the Elves/Maiar?
No fight, he hides before he even does anything. Pretty sure that Melkor could have used his help. Technically, this would be a stacked battle.
As there's no fight, it's not an adequate way to show how good Sauron was in combat.

Sauron+One Ring versus Elendil and Gil-Galad (whether or not Erenion had his ring is debatable)?
Gil-Galad and Elendil wrestle him down and weaken him, Isildur cuts the Ring off.
That summary makes the battle sound one-sided. The battle looked like going against Mordor until Sauron himself came out and did combat, and despite vastly outnumbered, he was still able to slay both Gil-galad and Elendil, which is no mean feat, and only three survived the battle with him. If anything, this battle shows his strength in combat.

Sauron+Army versus Ar-Pharazôn+Army?
The Númenórean king wins. He then seduces the king to attack Valinor, but he also loses his ability to change into a fair form after the Akallabeth.
Again, that wasn't even a battle. Sauron surrendered without so much as trading a blow. You can't judge his strength in combat on that.