richart
Major Champion
He's also won 2 slams before he was 25. All of the modern greats have, not some, all. You don't suddenly improve that much past 25 in the modern game
Lendl won 8 grand slams, the first one when he was 24 years old. He was also being written off before he won his first one at the French. Not sure that Murray being one year older means he should be written off.
Plenty of sportsman, including tennis players have peaked later in their career. Korda was 30 when he won his grand slam,Ivanisevic was 29. Johansson was 26 Krajicek was 25,Costa was 25, and they are all 25 year old plus who have won a grand slam in the last 15 years.