Beth Mead teed up Little to sweep past two defenders and fire home the opener six minutes before the break and the pair combined again seven minutes into the second half for Little to notch her 50th WSL goal.
Mead got on the scoresheet herself with a cool finish before Grace Fisk scored a late own goal to complete the rout.
Earlier on Sunday, Ria Percival struck deep into stoppage time to give Tottenham Hotspur a 1-1 draw with Manchester United, her free kick from far out on the left sailing past everyone and bouncing into the net to grab an unlikely point.
Manchester City hammered Leicester City 4-1 to leave the Foxes bottom of the standings with no points and fellow strugglers Birmingham City, who have amassed one point so far, were thumped 3-0 by Reading.
On Saturday, a Sophie Ingle goal gave reigning champions Chelsea a 1-0 win over Aston Villa, and Brighton & Hove Albion beat Everton 1-0 thanks to a strike from Aileen Whelan.
The weekend’s results leave Arsenal top of the table on 18 points, with Chelsea second on 15 and Tottenham two points further back in third.