Missing conversions cost Argentina's Jaguares dearly as they suffered a second successive Super Rugby home defeat of 13-8 to the Stormers.
Leading 2015 Rugby World Cup points scorer Nicolas Sanchez fluffed two relatively simple chances to add to his early penalty against the South African visitors.
The fly-half missed the conversion of a try by centre Jeronimo de la Fuente at the end of a first half in which all 21 points were scored before a large crowd at Estadio Jose Amalfitani in Buenos Aires.
Sanchez failed again on the hour as a slightly more difficult penalty attempt drifted wide to groans from supporters.
Replacement kicker Santiago Gonzalez Iglesias tried to trim the five-point gap with a more challenging attempt, but he was also off target.
Stormers fly-half Kurt Coleman had slotted two penalties and Sanchez had replied with one before the Argentine playmaker was sin-binned midway through the opening half for a professional foul.
The South Africans took advantage of the numerical advantage within two minutes as full-back Cheslin Kolbe jinked his way past several would-be tacklers to dot down.
Coleman converted for a deserved 13-3 lead. Once back to full strength, the hosts finished the opening half strongly and De la Fuente went over in additional time.
The Jaguares must wait at least until April 30 to celebrate a first home Super Rugby triumph after also committing many handling errors and lacking composure when within sight of the Stormers' try-line.
The Jaguares began life as a Super Rugby team by beating the Cheetahs and losing narrowly to the Sharks in South Africa.
After failing against the defensively superb Stormers, and also losing narrowly to the visiting Chiefs from New Zealand last weekend, they embark on a four-match tour.
The Jaguares meet the Blues, Hurricanes and Crusaders in New Zealand and the Sunwolves in Tokyo before hosting the struggling Kings in Buenos Aires.
The Stormers have a bye next weekend, then host the Sunwolves in Cape Town.
The victory increased their lead in the Africa 1 standings to eight points ahead of three-time Super Rugby champions Bulls.