Atletico coach Diego Simeone left talisman Antoine Griezmann midfielder Saul Niguez, defender Jose Gimenez and first-choice goalkeeper Jan Oblak at home for the trip to the Basque country to keep them sharp for Thursday's Europa League semi-final second leg against Arsenal, with the tie poised at 1-1.
Diego Costa made his first start after over two weeks out with a muscle problem, although Atletico's most dangerous player was winger Vitolo, who hit the post in the second half and later earned the first penalty which Torres squandered when he was pushed over by Ghana midfielder Mubarak Wakaso.
Torres's shot was beaten away by former Real Madrid goalkeeper Fernando Pacheco in the 71st minute but Atletico were soon awarded another penalty when Wakaso was again penalised, this time for blocking a shot by Torres with his arm.
Gameiro had only been on the pitch for 15 minutes and took penalty-taking responsibilities from Torres to break the deadlock in the 78th minute.
Atletico's Argentine winger Angel Correa was sent off deep in stoppage-time for picking up two successive bookings, one for a foul and the other for protesting at the decision.
Atletico are second in the standings on 75 points, four ahead of third-placed Real Madrid although they have played one game more and eight behind runaway leaders Barcelona, who will clinch a 25th Liga title if they get a draw or a win at Deportivo La Coruna later on Sunday.
(Reporting by Richard Martin, editing by Ed Osmond)
