Makazole Mpimpi scored two tries as the Kings beat the Jaguares 31-30 in Buenos Aires.
It was the Kings' fifth win this season and their third overseas, while the Jaguares – Argentina's Test team in all but name – have now suffered three consecutive home defeats.
The hosts outscored their opponents by five tries to four, but poor goal-kicking from Nicolás Sánchez and his replacement Joaquín Díaz Bonilla proved costly.
Juan Manuel Leguizamón opened the scoring when he barged over in the 17th minute, and the missed conversion was a sign of things to come for the hosts.
The Kings went 7-5 ahead, thanks to a Luzuko Vulindlu try, which came after they had kicked a penalty to the corner.
Sánchez slotted a penalty goal, but the visitors responded immediately when quick hands put Mapimpi over to make it 14-8.
The Jaguares then scored two tries to take a 20-14 lead, with Joaquín Tuculet's grubber finding Emiliano Boffelli, and Sánchez taking advantage of some poor Kings defence.
The hosts began the second half like they finished the first when Sánchez's grubber resulted in a try by Tuculet. But Lionel Cronjé's penalty clawed three points back for the Kings, and Sánchez then missed a penalty attempt in the 57th minute.
Soon after, Mapimpi scored his second try and Cronjé's conversion saw the Kings trailing 25-24.
Bonilla replaced Sánchez and missed his first penalty attempt at goal, before a great pass from Stefan Ungerer sent Wandile Mjekevu away for the Kings' fourth try.
With four minutes to go, Bonilla's cross-kick found Tuculet, who scored a try, but Bonilla's conversion went wide and the visitors hung on for the win.
Jaguares – Tries: Juan Manuel Leguizamón, Emiliano Boffelli, Nicolás Sánchez, Joaquín Tuculet (2). Conversion: Nicolás Sánchez. Penalty: Sánchez.
Kings – Tries: Luzuko Vulindlu, Makazole Mapimpi (2), Wandile Mjekevu. Conversions: Lionel Cronjé (4). Penalty: Cronjé.
Jaguares – 15 Joaquín Tuculet, 14 Matías Moroni, 13 Matías Orlando, 12 Bautista Ezcurra, 11 Emiliano Boffelli, 10 Nicolás Sánchez, 9 Martín Landajo (c), 8 Leonardo Senatore, 7 Juan Manuel Leguizamón, 6 Pablo Matera, 5 Matías Alemanno, 4 Guido Petti, 3 Nahuel Tetaz Chaparro, 2 Julián Montoya, 1 Lucas Noguera.
Subs: 16 Roberto Tejerizo, 17 Santiago García Botta, 18 Enrique Pieretto, 19 Ignacio Larrague, 20 Rodrigo Báez, 21 Gonzalo Bertanou, 22 Joaquín Díaz Bonilla, 23 Santiago Cordero.
Kings – 15 Malcolm Jaer, 14 Wandile Mjekevu, 13 Berton Klaasen, 12 Luzuko Vulindlu, 11 Makazole Mapimpi, 10 Lionel Cronjé, 9 Louis Schreuder, 8 Andisa Ntsila, 7 Tyler Paul, 6 Chris Cloete, 5 Wilhelm van der Sluys, 4 Irne Herbst, 3 Ross Geldenhuys, 2 Michael Willemse, 1 Mzamo Majola.
Subs: 16 Martin Bezuidenhout, 17 Schalk Ferreira, 18 Dayan van der Westhuizen, 19 Lubabalo Mtyanda, 20 Thembelani Bholi, 21 Stefan Ungerer, 22 Masixole Banda, 23 Yaw Penxe.
Photo: Juan Mabromata/AFP Photo