So apparent was the episode that players on the field, 32 minutes into the game, immediately began waving for medical assistance and fans in the stands at Rio Tinto Stadium yelled for personnel to run rather than walk onto the field with a stretcher.
After the game, a Monarchs' spokesman said Holness was alert and responsive to medical treatment.
"It's something none of us have ever witnessed, at least I haven't," Monarchs' coach Freddy Juarez said. "Our prayers are with him and our players were very supportive."
Holness was taken off the field by ambulance after a 30-minute delay.