The Netherlands striker completed a hat-trick inside 39 minutes to give the Gunners a 3-0 half-time lead away from home against the Czech Republic outfit.

Miedema added a fourth after the break and Kim Little's penalty made it 5-0.

The hosts' Katerina Svitkova and Mia Persson pulled goals back late on but Arsenal take a 5-2 lead back to London.

The Gunners will progress to the last eight if they avoid a heavy home defeat on 31 October.

Arsenal - last season's Women's Super League champions - were 6-0 aggregate winners over Italian side Fiorentina in the previous round to reach this stage.

Miedema, 23, also scored three goals over the course of that last-32 tie.