Patients presenting to the emergency department with an acute ischemic stroke due to a large vessel occlusion eligible for thrombectomy and target mismatch on computed tomography perfusion imaging within 24 hours of onset will be assessed determine their eligibility for randomization into the trial. If the patient gives informed consent they will be randomised using a central computerised allocation process to either standard of care (no intravenous thrombolytic treatment or intravenous alteplase 0.9mg/kg) or tenecteplase before undergoing intra-arterial clot retrieval. The trial is prospective, randomised, open-label, blinded endpoint (PROBE) design.