I did a little research on Superman v. Wonder Woman. No confrontation between the two that I found had a definitive winner. The most brutal recent one was when Superman was mind controlled, which seems to always happen, and he thought Wonder Woman was Doomsday, who had just killed Lois.
Superman is stronger and faster, but Wonder Woman is more trained and a more efficient fighter. She would negate Superman's raw speed with her instincts. But even the current Superman is significantly stronger. In one recent comic, he bench pressed the equivalent of the Earth's weight for 5 days.
Superman is no slouch in the trained/fighting department though, which is why he would fare better against Wonder Woman than Supergirl, who has nowhere near Superman's experience (also depicted when Supergirl and Wonder Woman fought).
Wonder Woman got her shots in but took a hell of a beating too, including Superman crushing one of her bracelets and breaking her wrist.
Wonder Woman concluded that the best thing to do was not win the fight, but stop the guy who was controlling Superman, so she focused on just slowing Superman down.
What was amazing is Wonder Woman was forced to break that person's neck to release Superman, killing him. Superman of course was shocked by all of that, but that's another topic.
Other battles I found showed Wonder Woman and Superman holding their own against each other, but neither conclusively winning. The battles always seem to get stopped before there is a real winner unless there is an alternate reality, and in those cases, I found examples of each winning.
The thing is, battles involve strategy. Different opponents would bring out different techniques. In boxing for example, if a fighter is known to be brutally strong, who ends fights early, the goal is to tire that fighter out and go for the kill later. See Clubber Lang. If a fighter is not as strong as you, maybe going toe to toe is a better strategy.
So Superman thinking he is fighting Doomsday (or on Supergirl, Zod), might lead to a different strategy when fighting Wonder Woman.
Case in point:
In an alternate reality, where Superman and Batman grew up together, but of course evil, Wonder Woman killed Batman. Superman, in revenge, kills Wonder Woman.
But then there was a story called Injustice: Gods Among Us, where I guess they were all evil, and Wonder Woman beat that version of Superman. Superman had the upper hand in a fight to the death, but instead of just killing her, he urged her to surrender. That hesitation turned the tide in Wonder Woman's favor. But it's also in character, even in an alternate reality. Superman would be more likely to hesitate than Wonder Woman, who is more trained and unafraid to kill when needed.
Basically, it's not conclusive. The only one that could stop Wonder Woman would be Superman, and vice versa.
Both of them however, would be able to beat Supergirl, which all comes back to the episode, where the writers felt the need to tear down Superman to pump up the title character--something that was just unnecessary.