Monreal's back pass did not have enough power on it, allowing Niasse to steal the ball from Cech and tap into an empty net.
Take a look at the comical mishap here:
Y esto es lo mas ridiculo que veran hoy.
— Yo era @Mcgrowfinal (@amadisimo_lider) 22 de outubro de 2017
Monreal y Cech se hacen relajo solitos.pic.twitter.com/x4PZPNlj3C