"There are some really good players, very impressed with the standard here. The challenge for them is the physicality of the game -- how fit, how strong you can get... also the mental side of things... the intensity, the concentration to keep playing well from the first ball to the last ball," Henman told IANS at the launch of a pilot scheme -- 'HSBC Road to Wimbledon', first Wimbledon event outside Britain.

"Tennis doubles and singles is almost like two different sports," said Henman.