With the three overnight leaders - Robert Karlsson, Johan Edfors and Maarten Lafeber - amongst the afternoon starters, South African Schwartzel and Ireland's McGrane both joined them on eight under par.
Schwartzel, fifth on The Race to Dubai after an impressive season, opened with a birdie at the tenth and added two more in his first eight holes.
McGrane also started on the back nine with a birdie, and picked up shots at the 12th and 14th to be three under for his round through six holes.
With five tied at the top, no fewer than six players were level a shot behind.
Sweden's Alexander Noren was yet to tee off, but had already been joined on seven under by English duo Gary Boyd and Richard Finch, South African Hennie Otto and Ryder Cup star Edoardo Molinari, while Mikko Ilonen of Finland was level par for the day after five holes having been level with Noren in fourth overnight.