RE: For the Chef's...need help
#1---Did you use any type of salt??
Salting with garlic salt, table salt, season salt, ect., will help dry the meat out due to the fact that it removes the remaining moisture. Use fresh ground spices and powders instead of salts.
#2---Did you turn the meat often??
The more it is turned, the tougher it will become because the heat draws out the juices on the upper side of the meat in the form of blood globes. Try to turn it as little as possible next time, once for a few minutes on each side is enough.
#3---Did you use high heat?
The faster you cook it, the less the moisture escapes from inside the cut.