It was Thurstan's maiden win over their old adversary with whom they had unsuccessfully battled in 24 encounters since their first meeting in 1965.
During that period Royal had defeated them seven times with 15 encounters ending in draws and two matches abandoned.
Off-spinner Chamara Liyanage carved out Thurstan's historic victory with a match bag of nine wickets for 62 runs. He also contributed his bit with the bat making 43 out of his side's first innings total of 255 for 9 declared.
Royal bowled out for 132 in their first innings, put up a slightly better display in the second to total 195, but Thurstan enjoying a first innings lead of 123, were left with 73 for victory a target which they achieved in 21 overs losing half the side.
Royal 132 and 195 (A. Samarakody 46, L. Liyanage 47, S. Sinnetam- by 14, K. Nanayakkara 66 n.o., C. Liyanage 4 for 42, H. Boteju 3 for 62, S. Samarasinghe 2 for 58)
Thurstan 177 for 4 contd. 255 for 9 decl. (C. Liyanage 43, S. Nanayakkara 26 n.o., T. Wickremasinghe 26, L. Liyanage 2 for 67, A. Watawala 3 for 55) and 73 for 5 (N. de Silva 17, H. Boteju 20, S. Bandaratilleke 17, L. Liyanage 4 for 36) - (S.T.)