How strong is Marin at the peak of table tennis?

Marin is a table tennis player in China, who has won the world championship, the World Cup championship and the Olympic gold medal for many times. His peak was during the men's singles World Championships in 2005, and he and Wang ranked in the top two in table tennis all the year round. Marin won the World Cup four times in a row and was called "Mr. World Cup". However, although Marin won the world championship of 18 before retiring, she had her own difficulties. He reached the World Championships three times, missed the gold medal three times, and finally missed the Grand Slam.