Grey Tango was purchased and imported in 1971 with a foal out of Stonewall Starfire, called Starfire Rhythm, at foot. This colt's name was shortly thereafter changed to Mr USA. She was imported by Bill Sieberhagen for Basjan Steyn and then both sold to Fanie Naude of Vida Saddle Horse Stud.

Mr USA won the S.A. Grand Champion Fine Harness Title in 1981. He sired several great horses which turn out as great sires. One of them was Yokozuna.