Schwartzel leads by 10 shots at Alfred Dunhill

The South African birdied five of his first eight holes and then had four birdies in a row from No. 12 to sit at 21 under. The 2011 Masters champion repeated the dazzling form that won him the Thailand Golf Championship by 11 shots last week.

Bourdy was alone in second at 11 under.

Sweden's Kristoffer Broberg, South Africa's Branden Grace and England's Steve Webster were 11 shots off the lead in a tie for third at 10 under.