Who are Athletic Bilbao? Arsenal’s first Champions League opponents explainedArsenal kicks off their Champions League campaign against Athletic Bilbao on Tuesday at 5:45 pm. This marks Bilbao’s second time hosting a Champions League match at San Mamés. Bilbao qualified for the Champions League for the first time since 2014, overcoming recent setbacks including Yeray Álvarez’s doping suspension and Aymeric Laporte’s delayed registration. Nico Williams’ fitness is also a concern for Bilbao.