I didn't mean final match as in the whole fight. I meant the VERY final match between aces. I remember all the crazy Frenzy Plant spam Sawyer tossed, and he's supposed to be the genius trainer. He really had NO strategy to deal with Ash's Greninja other than "let's hit him hard!"
Many people forget just how big the strength gap between Ash-Greninja and Mega Sceptile really was; Ash-Greninja was significantly stronger than Mega Sceptile despite the type disadvantage. Remember that Mega Sceptile was on-par with an E4 base ace, whereas Ash-Greninja was on-par with an E4 Mega Ace (albeit still weaker than MCX who was even stronger). Sure, Ash-Greninja didn't dominate Mega Sceptile, but Ash-Greninja was never at risk of actually losing that battle (unlike say, Infernape vs Electivire which was much more evenly matched by comparison).
The reason that Ash didn't use much strategy against Mega Sceptile (aside charging the massive Water Shuriken) was because he didn't need to, since Ash-Greninja was much stronger than Mega Sceptile. So Ash didn't need to use strategy to beat Mega Sceptile, just as Paul didn't need strategy to sweep Barry 3-0. At a certain point, strategy becomes worthless compared to raw power. For example, no amount of "strategy" would allow someone like Barry to defeat Paul's Electivire in a 3v3 battle. The power gap is just too big.
Even in the Ash vs Sawyer battle, most of the strategy came from Sawyer because he needed strategy to try and make up for his inexperience as a trainer compared to XY Ash. Especially when it came to Pikachu and Greninja, let alone Ash-Greninja. Ash's most notable strategy in that battle was Pikachu vs Aegislash, and that was because Pikachu was at a disadvantage despite being stronger in terms of raw strength. Ash couldn't just brute force his way through Aegislash because of King's Shield.
A slightly similar thing happened in the Ash vs Paul battle (albeit far less because Paul was far more experienced than Sawyer), the main strategies used were mostly by whoever was at a disadvantage in the moment. The main exception being Paul's tactical use of using Aggron and Gastrodon as scouts, but aside from just using Toxic Spikes, Paul never used strategy with Drapion. Why? Because Drapion could sweep half of the DP team, not including Pikachu or Infernape. Paul never needed strategy to sweep Buizel, Staraptor, and Torterra because Drapion was far stronger than them.
Paul's actual main strategies came involving Gastrodon, Ninjask, and Froslass. Gastrodon was one of the two scouts baiting out Ash's team, while Ninjask and Froslass had to fight opponent's much stronger than themselves (Infernape and Pikachu respectively) so Paul needed strategy to make up for being at a disadvantage power-wise. Why? Because we all know Paul's Froslass had no chance in hell of beating Pikachu in a clash of raw power, so Paul tried to make use of Froslass' Snow Cloak and Hail to wear Pikachu down to make up for the strength gap. Yet as Ash proved against both Paul and Sawyer, being strategic can only get you so far. Even with Sawyer's Slaking, Ash did so much damage that it couldn't recover it all off and it allowed Talonflame to beat it, showing that just using brute force is usually the best strategy of all.
Just because people want to overrate SM doesn't change the fact that Ash was
OBJECTIVELY a far more competent trainer in DP and XY, as well as the BF. Even the Kahuna were weaker than the gym leaders, hence Brock using his non-ace Sudowoodo against Olivia's ace. Anyone who unironically thinks that Gladion is in the same league as Paul or Sawyer is just objectively wrong. Gladion only really looks strong compared to SM Ash, and all the weak trainers who entered the Alola League (i.e. everyone who wasn't Ash/Gladion/Kiawe/Guzma).
It doesn't help that Gladion's tank Lycanroc lost to Kiawe's Turtonator which, while a pretty decent Pokemon compared to other companion aces, is the same Pokemon that lost to Brock's Mega Steelix... and this isn't even mentioning the fact that base Steelix took a super-effective Z-Move (albeit took considerable damage and Brock praised the attack). Granted, Kiawe obviously trained between that battle and the League, but I doubt it got that much stronger given Kiawe wasn't doing the Island Trials like Ash and Gladion (so his team got much less experience than Ash/Gladion's Pokemon).
But considering that Kiawe beat Olivia despite being at a major disadvantage, yet lost to Brock despite having a major advantage over him, it reinforces the fact that Olivia's Lycanroc would have lost pretty easily to Brock's base Steelix if they fought. The fact that Gladion's Lycanroc lost to Kiawe's Turtonator goes to show that Gladion was overrated, and that Kiawe was actually underrated. I don't think many will disagree when I say Kiawe was a much better rival to Ash than Hau ever was, despite the fact Kiawe was never really written as a rival (whereas Hau is a rival in the games like Gladion).