Madsen also had five birdies and two drops to sit one off the pace alongside Crespi.
Otto, the 2011 champion, fired the round of the day to put himself in contention on Sunday despite a triple bogey seven on the par-4 No. 9. Otto responded to that slip with seven birdies in his last eight holes to move into fourth.
Italy's Andrea Pavan and Spain's Alejandro Canizares are tied for fifth on 11 under and Sweden's Magnus Carlsson is a shot back in a tie for eighth.
Two-time U.S. Open winner Retief Goosen is still just about in contention for a first tournament win since March 2009 after his 70 on Saturday. Goosen is six shots back on Schwartzel after lifting himself with five birdies on his second nine following three dropped shots going out.
Former British Open champion David Duval of the United States and European Ryder Cup captain Paul McGinley of Ireland missed the cut.