Everton looked good value for a point until the third minute of added time when James unleashed a long-range effort with her left foot that clipped the post and found the back of the net.
Arsenal thrashed north London rivals Tottenham 5-0 at Emirates Stadium but Chelsea maintained their seven-point lead at the top of the WSL with a late 2-1 win over Everton.
Everton threatened to cause an upset when Kelly Gago burst down the left wing in the 51st minute and unleashed a fine effort into the top corner against the run of play.
Clare Hunt's 15th-minute own goal set Arsenal on their way and Mariona Caldentey added a second 10 minutes before half-time.
Lauren James then scored a 93rd-minute winner as Chelsea battled from a goal down to beat Everton at Kingsmeadow.
