The phrase "top level" refers to the highest or most important level of something. It represents the most significant or superior position in a hierarchy or ranking. Full definition
His gambling does not stop him knowing the game he played at top level for his whole career, virtually. (justarsenal.com)
These are complemented by top levels of service from an exceptional team of staff headed by a knowledgeable villa manager and including an experienced, talented chef and a driver. (luxuryretreats.com)
Sleep at tree top level in the jungle, inspire your sense of adventure and free your spirit. (thefamilytravelfiles.com)