I am looking for words or expressions that I can use to describe the most successful team/individual in a tournament/competition (having won it the most times, like Brazil at the FIFA World Cup.) One word I can think of is "most-decorated", but that seems to only apply if the winning team receives a major award for and it wouldn't be as appropriate if it's a gaming/chess tournament. I am also aware of the term "winningest", but that sounds awkward and really informal. Appreciate any suggestions.
Winningest, or if you want to go all-in, All-time winningest.
Don Shula won 392 games in 26 years as the head coach of the Miami Dolphins. Combined with the 98 wins he racked up in seven years with the Baltimore Colts, Shula is the winningest coach in NFL history with 490 victories.
All-time winningest Division I basketball coaches
Reigned and ruled can be used in similar sense but only when you are talking about a span of time.
Example: Michael Phelps ruled the swimming world from 2000 to 2016.