That's not my point. I'm going to break down the fight between Sidious and Mace for you to understand.We'll be using this (https://www.youtube.com/watch?v=q0r4jNhG9Z4) as reference.
1:08 to 1:17: Walking into this fight, Mace is not expecting anything close to the level of ability Sidious immediately displays. He's completely unprepared for the shock and awe that is Sidious' style, which is reflected in his hesitant attacks toward Sidious. If you look at what Mace does, he is primarily probing at Sidious' defenses, overall uncommitted to launching any devastating offensive.
1:18 to 1:29: Mace is on a full-fledged retreat. He's not attacking Sidious - he's defending from Sidious' attacks. You have to consider that, while Sidious has been dreaming and preparing of a fight like this for his entire life, Mace hasn't. The Jedi just finally came to terms that Dooku is not the primary Sith Lord a few months before this fight. However, as the fights continues, Mace is visibly becoming more confident in his abilities, particularly at 1:25.
1:30: The moment you keep on citing. As noted before, Mace became more and more confident throughout the hallway sequence since Sidious' attacks weren't going anywhere. In this particular moment, Mace's arrogance reaches a point where he left himself open to an attack. That being said, the fact Sidious does not strike down Mace, Anakin aside, can easily be seen as a moment of arrogance on Sidious' part. Sidious is under the impression he, as a Sith Lord, is the blatantly superior fighter and can continue this fight for the shits and giggles, but as Mace comes into his own and Sidious' allusion of fear wears off, this changes.
1:31 to 1:37: Mace rebounds. There is no reason to believe Sidious is toying with Mace here. Lucas intentionally shot the fight the way he did so that we could see the facial expressions of the characters for this particular close-up. Sidious seems to want to be smiling, but he's not. He's in pain and is in a uncomfortable position. Mace has the upper hand here.
1:52 to 1:58: Here, Mace assumes a position of supremacy over Sidious, hence the hiss of hatred at the end. What I mean by that is Mace is now the one who is pushing Sidious toward the balcony, not the other way around. Sidious' visible expression of anger expresses this.
1:59 to 2:03: Mace is an offensive fighter. Here, finally, he's able to show what he can do. He launches what I'd consider the most effective straight-on assault in Star Wars. Sidious tries to change the flow of the fight with his Force-powered leaps and acrobatics, but notice he fails to and Mace continues his march toward the balcony. Sidious is visibly frustrated over his failed attempts to reassume the lead.
2:04 to 2:11: Sidious does pretty well here. He forces Mace to switch positions with him, but ultimately his offensive isn't working as effectively as it was toward the start of the fight.
2:12 to 2:18: Here's where Mace's late-game superiority is blatantly obvious. Sidious launches a final offensive, but Mace not only handles it, but then switches their positions as Sidious is attacking. It's incredible.
2:19 to 2:23: Mace's reassertion of territory ultimately ends the fight. Sidious is swiftly disarmed.
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The idea of Sidious throwing the fight is not something that can be used as an actual argument, since it's never explicitly stated. That being said, you have the idea that Sidious letting Mace win and Mace being able to defeat Sidious are mutually exclusive. They're not. Sidious could have recognized that Mace was taking the advantage and opted to end the fight on his own terms (i.e. placing himself in a position where Mace would disarm him) rather than have the fight continue and be outright killed.
Otherwise, it just gets far too complicated. We know, for a fact, that Mace is in the same heavy-weight class as Sidious. George and Nick said so. Also, Gillard's statement that Mace is bordering 8 and 9 supports the idea he was losing early fight (as an 8) but gained the advantage late fight (as a 9). Anyway, the idea Sidious was "toying" with Mace is contracted by these comments. Clearly Mace can give Sidious a run for his money and perhaps even beat him, which is exactly what happens once he gets in the grove of things.