The Gunners hit their hosts for six at Bishop's Stortford's Woodside Park with Gemma Davison (2), Ellen White (2), Jordan Nobbs and Kim Little causing the damage.
After a tight opening 25 minutes, Davison's opener was the only thing that separated these FA Women's Super League title-chasing rivals.
However Shelley Kerr's side soon got into their stride starting with a Nobbs screamer from 25-yards before White, set up by Rachel Yankey, ensure Blues were 3-0 down at the interval.
Yankey and White combined again shortly after the break with the latter calmly stroking home after being played in on goal.
Davison set up Little for number five before going on to complete her brace by rounding substitute goalkeeper Mary Earps, on for Marie Hourihan, late on.
Arsenal Ladies: Byrne, Scott (Beattie 57), Flaherty, Grant, Fahey, Houghton (C), Nobbs, Little, Davison, Yankey (Carter 69), White.
Subs not used: Spencer, Tracy, Ludlow.
Blues Ladies: Hourihan (Earps 69), Weston, Harrop, Bassett (C), Unitt, Simpkins, Moore, Potter (Torkildsen 63), Westwood (Wilkinson 65), Christiansen, Williams.
Subs not used: Haines, Linnett.