Schwartzel had five birdies against two bogeys Saturday and is at 15-under 201 after three rounds.
Crespi, who was tied with Schwartzel for first after Friday's play, shot 70 Saturday. He is tied for second with Morten Orum Madsen.
The three players' hole-by-hole scores were almost identical.
Hennie Otto had seven birdies in the last eight holes and jumped into fourth place at 13-under overall. His round of 65 included a triple bogey 7 at the ninth hole.
Crespi and Schwartzel each played the front nine in 2-under. Both had birdies at the second, sixth and eighth holes. Schwartzel had a bogey at the fourth hole but Crespi fell back into a tie for first with a bogey at No. 5.
Schwartzel pulled ahead with a birdie at the 10th and both players went birdie-bogey on 15 and 16.