Samurott @ Lum Berry / whatever you want as it hit a Focus Blast in most case.
Ability: Torrent
EVs: 252 Atk / 4 SpD / 252 Spe
Lonely Nature
- Grass Knot
- Waterfall
- Aqua Jet
- Swords Dance
Poliwrath usually like to switch in against SD Samurott to wall it. But with Grass Knot, if you catch his switch, you win the 1v1 even without rocks, unless an unfortunate sdef drop on Focus Blast, Grass Knot also help Samurott to deal with Gastrodon more easily.
0 SpA Samurott Grass Knot (80 BP) vs. 96 HP / 0 SpD Poliwrath: 136-160 (39.4 - 46.3%) -- guaranteed 3HKO after Leftovers recovery
While Poliwrath can't 2HKO you with Focus Blast + Vacuum Wave, even with two high roll, as said before, unless a drop.
.
252+ SpA Poliwrath Focus Blast vs. 0 HP / 0 SpD Samurott: 193-228 (58.3 - 68.8%) -- guaranteed 2HKO after Stealth Rock
252+ SpA Poliwrath Vacuum Wave vs. 0 HP / 0 SpD Samurott: 66-78 (19.9 - 23.5%) -- 24.8% chance to 4HKO after Stealth Rock
Megahorn could've also win the 1v1, but you need to be at +2 and to hit 3 megahorn.
252+ Atk Samurott Megahorn vs. 96 HP / 0 Def Poliwrath: 62-74 (17.9 - 21.4%) -- possible 7HKO after Leftovers recovery
+2:
+2 252+ Atk Samurott Megahorn vs. 96 HP / 0 Def Poliwrath: 124-147 (35.9 - 42.6%) -- 94.9% chance to 3HKO after Leftovers recovery