LogFAQs > #932168181

As far as Ace goes, the only games really worth mentioning imo are the one at the very start (Seidou vs Komadai Fujimaki, probably better nominated as Satoru Furuya vs Hongou Masamune honestly) and around the 1/3 mark (Seidou vs Ichidai). The back half has had several games, but I wouldn't say any of them are worth bringing up here. The manga has an Ichidai vs Yakushi game that I will absolutely tell people to watch and nominate once the anime covers it, but that's probably not until late 2020 assuming the anime doesn't take any breaks.

If you're looking at sports series in general, I'd look towards the Hakone Ekiden (Run With The Wind) before looking at either of the Ace matches I mentioned, though. That was entirely in the second half of the anime, so it should be valid unless you dispute it being a fight/match. If it counts though, I'd say it deserves top billing overall.