Atletico Madrid beat Athletic Bilbao 1-0 in the first leg of their Copa del Rey quarter-final tie on Thursday night.
Diego Godin scored the only goal of the match for the holders at the Vicente Calderon in the 41st minute when he got on the end of a brilliant right-wing cross from Koke to power an unstoppable header past Iago Herrerin.
Atletico had chances to build a bigger lead to take to San Mames for the second leg, but Herrerin did superbly to deny Diego Costa, Adrian and Raul Garcia.
Atletico won the cup for the first time since 1996 last season when they stunned arch rivals Real Madrid in the final, winning 2-1 at Bernabeu, while Athletic's record of 23 Copa del Rey crowns is second only to Barcelona (26).
The two sides meet in the second leg next Wednesday.