At the final whistle, Williams couldn't contain his excitement. 'Playing at Old Trafford is a dream come true,' he gushed. 'It's an incredible stadium. We have to put on a great show at home and then head to Manchester for the second leg. United are a fantastic team, and we're going to go there with a lot of ambition.'

Williams also reflected on Athletic's remarkable season. 'I think we're doing something extraordinary,' he said. 'Last year we won the Copa del Rey, and now we're in the Europa League semi-finals. I hope we can reach the final. The team is doing everything necessary to get there.'

On the victory at San Mames, Williams continued, 'We're happy, but we have to keep pushing. That's our only goal.'

Williams also had kind words for his teammate, Oihan Sancet, who scored the winning penalty. 'Oihan is an incredible player,' he said. 'Sharing a locker room with him is a blessing. He's one of the best penalty takers Athletic has ever had, and I'm very proud of him.'