Both noted for their quickness and power, Mainaky and Subagja won over thirty international titles together, including all of badminton's major championships at least once.

Five of seven children in the Mainaky family, Rexy, Richard, Marleve, Rionny and Karel, were part of the Indonesian national shuttling team in the 1990s and nowadays they still have a hand in the sport, though courtside as badminton coaches.

Men's doubles Men's doubles Mainaky is known amongst his peers and colleagues, and the game's fans, as one of the greatest doubles player of all time,[citation needed] alongside players such as Christian Hadinata, Tjun Tjun, Johan Wahjudi, Liem Swie King, Ricky Subagja, Tony Gunawan, Hendra Setiawan, Park Joo Bong, Kim Dong Moon, Fu Haifeng, Cai Yun, and Finn Kobbero.

[citation needed] He was the coach to English badminton mixed doubles' pair Gail Emms and Nathan Robertson and successfully brought them winning the 2004 Summer Olympic silver medal, 2005 All England Open Badminton Championships and 2006 IBF World Championships titles.

He coached the Malaysian National Team's Doubles department and his biggest success was bringing up Koo Kien Keat and Tan Boon Heong.

[3] However, there was rumours about a fall out between Koo Kien Keat and Tan Boon Heong with Rexy as the pair requested for a change of coaches.