MADRID — Iñaki Williams scored six minutes into stoppage time as Athletic Bilbao won 2-1 at Valencia to reach the semifinals of the Copa del Rey on Wednesday, and its Basque Country rival Real Sociedad made it to the last-four by winning 3-2 at Alaves.Athletic will be playing in its sixth Copa semifinal in seven seasons. It won the title in 2024 and was runner-up to Barcelona in 2020-21 and to Sociedad in 2019-20.Williams scored the winning goal with a left-footed strike from the middle of the area after a cross by his younger brother Nico Williams following a breakaway. Athletic, which was winless in three matches across all competitions, had taken the lead in the 26th after an own-goal by Umar Sadiq, who also equalized for the hosts in the 35th. Athletic’s Mikel Jauregizar missed a 75th-minute penalty.Before the match, Spanish media reported that fans threw several objects at the bus carrying Athletic’s players. The victory comes a few days after a mural with drawings of Iñaki and Nico Williams was vandalized in Bilbao, where some fans have criticized them.Young Iceland forward Orri Oskarsson scored an 80th-minute winner for Sociedad, which will be playing in the semifinals for the third straight season. It last reached the Copa final …