Chennai: Ghazal and playback singer Hariharan feels his collaboration with A.R. Rahman has resulted in several chart-busters because the double Oscar-winning composer deeply understands his singing capabilities. "He knows me as a singer in a very, very deep way. He understands my singing capability and knows exactly how to stimulate me with his music," Hariharan told IANS. Some of Rahman-Hariharan combo's best songs are "Chanda Re", "Hai Rama", "Tuhi Re", "Ay Hairthe" and "Chandiranai Thottathu" among others. Asked if one could look forward to collaboration with Rahman in near future, he said: "Time will tell."