Piet Norval defeated Jacco Van Duyn 7-5 7-6 in the Great Britain 2 Masters 4 semi-final on hard.
Norval P. took it in straight sets.
Piet Norval beat Jacco Van Duyn 7-5 7-6. Umpiry, "Piet Norval vs Jacco Van Duyn — Great Britain 2 Masters 4 Semi-final", https://umpiry.com/match/1991-04-22/duyn-vs-norval-great-britain-2-masters-4-sf?utm_source=cite (as of 22 April 1991).