World No. 4 Rafael Nadal says he is taking a humble approach in Madrid as he is hoping his return goes well and he finishes the tournament in positive spirits. Nadal hasn’t played in any events so far this clay season as a rib injury forced him to withdraw from Monte Carlo and Barcelona. Nadal hasn’t played a tennis match in a month and a half and he admits it won’t be easy in Madrid since he is lacking matches. “I have improved compared to when I arrived here [in Madrid], but I still have ups and downs, bec …