Johannsson, who took his Eredivisie scoring tally to 17 on the season, missed out on several opportunities to make that number even larger. The most frustrating was a stoppage-time miss that flew over the crossbar.
The 23-year-old's goal was well taken. He weaved back and forth at the center back before bursting free to head in a cross from Steven Berghuis.
Earlier in the match, he was involved in a strange incident in which Roda defender Guy Ramos appeared to grab for Johannsson's genitals. Ramos wasn't punished for that incident but was booked in the 67th and 81st minutes en route to a sending off.