Carlos Costa defeated Paul Haarhuis 4-6 6-4 6-3 in the Hamburg quarter-final on clay. The upset overturned the form book — Paul Haarhuis came in defending last year's round of 32.
Costa C. came through in three sets.
Carlos Costa beat Paul Haarhuis 4-6 6-4 6-3. Umpiry, "Carlos Costa vs Paul Haarhuis — Hamburg Quarter-final", https://umpiry.com/match/1992-05-04/costa-vs-haarhuis-hamburg-qf?utm_source=cite (as of 4 May 1992).