Friday's Porto 2 quarterfinal pits Gustavo Heide against Thiago Monteiro on clay. Gustavo Heide has won 6 of the last 10. Thiago Monteiro has won 6 of the last 10.
Gustavo Heide simply rates much higher on clay, and our number follows from it. The edge belongs to Heide — real, but not the kind you take for granted at this level.