Jan Siemerink defeated Luis Herrera 7-6 7-6 in the Singapore round of 16 on hard. The result followed the form book — Jan Siemerink came in defending last year's round of 16.
Siemerink J. took it in straight sets.
Jan Siemerink beat Luis Herrera 7-6(2) 7-6(5). Umpiry, "Jan Siemerink vs Luis Herrera — Singapore Round of 16", https://umpiry.com/match/1991-04-22/herrera-vs-siemerink-singapore-r16?utm_source=cite (as of 22 April 1991).