Crusaders captain Ryan Crotty admitted that did not execute their game plan as well as they should have against the Sharks who "played smart".
A fourteen-man Sharks team ended the Crusaders five match winning streak against all teams.
The Sharks lost Jean Deysel to a red card for stamping on Crusaders player Jordan Taufua's head.
The victory was also the Sharks first over the Crusaders in Christchurch and the first South African victory over the Christchurch team since 2001.
The result was a blow for the Crusaders' playoff hopes as they are about to embark on a period of canabalism in the New Zealand conference where local team will be playing against each other.
The Crusaders started the match in fifth place and could have gone to the top of the standings but even though the Crusaders had an extra man for three quarters of the match they could only take a losing bonus point from the contest.
The Crusaders appeared to lack any urgency after the sending off and in 10 minutes after Deysel's dismissal they enjoyed an 81 percent territorial advantage but they were unable to find a hole in the Sharks defence.
The second half was much of the same although the Sharks showed more ambition and in the end outscored their hosts by three tries to one.
"It's disappointing to let that one get away," Crusaders captain Ryan Crotty said.
"They did well to slow the game down, they played smart and we didn't execute as well as we should have."