Saracens condemned world champions South Africa to a third consecutive tour defeat on an extraordinary night for the club at Wembley Stadium. The former South Africa fly-half Derick Hougaard returned to haunt the Springboks with 14 points, including the match-winning drop-goal six minutes from time.
Saracens had trailed 18-6 at the interval but hit back with tries from No 8 Ernst Joubert and Brad Barritt.
Saracens attracted a crowd of 46,281 to Wembley, who saw the club start with seven South Africans plus England international Michael Horak and Barritt, who were both born in the country. The Springboks side featured five players who played in the Lions Tests, including fly-half Morne Steyn.
South Africa looked to have won the game late on when Jongi Nokwe scored his second try, but Saracens refused to be beaten. Hougaard dragged them back to within two points with a penalty and then sparked wild celebrations with the match-winning drop-goal.
Sarries' South African coach Brendan Venter said: "There were no league points on offer but we will remember this night for a long time to come."
Saracens: Tries Joubert, Barritt; Con Hougaard; Pens Hougaard 3; Drop Goal Hougaard. South Africa: Tries De Jongh, Nokwe 2; Con Pienaar; Pens Pienaar 2.
Saracens: Horak; Cato, Ratuvou, Barritt, Tagicakibau; Hougaard, De Kock; Gill, Reynecke, Skuse, Botha, Vyvyan, Van Heerden, Melck, Joubert. Replacements: Nieto for Horak, 49; Penney for Cato, 40; Barrett for De Kock 38; Brits for Reynecke, 40; Goode for Skuse, 49; Saull for Melck, 47.
South Africa XI: Rose; Ndungane, De Jongh, Olivier, Nokwe; Pienaar, Adams; Van der Merwe, Strauss, Van der Linde, Hargreaves, Bekker, Deysel, Potgieter, Johnson. Replacements: Viljoen for Olivier, 68; Bosman for Pienaar, 68; Hougaard for Adams, 40; Maku for Strauss, 68; W Du Preez for Van der Linde, 10; Rossouw for Bekker, 40; Raubenheimer for Johnson, 68.
Referee: J Jones (Wales).