Here is a slightly different approach that closes output files when a new output file is specified in the input and uses the default field separator (any combination of contiguous <space> and <tab>...
# Set <tab> and <space> as field separators
awk -F'[\t ]' '
# If NF (number of fields) in current input record == 1, set ofile variable = $1 (output filename)
# next forces awk to immediately...