diff --git a/components/match2/commons/match_group_input.lua b/components/match2/commons/match_group_input.lua
index 388530e386..5014fab67d 100644
--- a/components/match2/commons/match_group_input.lua
+++ b/components/match2/commons/match_group_input.lua
@@ -348,10 +348,12 @@ function MatchGroupInput.applyOverrideArgs(matches, args)
 	end
 end
 
+---@param matches {match2opponents: table[]}[]
+---@return integer
 function MatchGroupInput.getMaxOpponentCount(matches)
 	return Array.reduce(matches, function(cur, match)
 		return math.max(#match.match2opponents, cur)
-	end)
+	end, 0)
 end
 
 ---@param headerInput string?