Szczesny is likely to be key to Arsenal 's success -- he was when the two teams met last year , pulling off a fantastic save from a Robin van Persie attempt -- .
A poor showing may up the need for Cech .
Szczesny is likely to be key to Arsenal 's success -- he was when the two teams met last year , pulling off a fantastic save from a Robin van Persie attempt -- but a poor showing may up the need for Cech .