Brother of fellow tennis player Marie Castendijk (later Driebeek) with whom Gerard won the mixed doubles event at the Dutch National Championships in 1924.
Round 1
Gerard Castendijk 1 *
bye
Round 2
Gerard Castendijk 1 *
Mr. Furnee
w.o.
Round 3
Gerard Castendijk 1 *
Marinus Cornelis (Dick) Sigmond
6-1
6-1
Round 4
Gerard Castendijk 1 *
E. Halkema
6-3
6-1
Quarterfinals
Gerard Castendijk 1 *
Hendrik (Henk) Timmer
w.o.
Semifinals
Mr. de Beer 1 *
Gerard Castendijk
6-0
9-7
6-4