Wilkinson put Rangers ahead inside the opening 10 minutes at K Park Stadium, glancing her header home after a smart delivery from Lizzie Arnot.
Wilkinson continued to probe and came close to a second as she hit the crossbar, with a Kirsty Howat effort also going close.
Motherwell almost found a late equaliser through Lucy Barclay but Rangers goalkeeper Jenna Fife got down well to maintain her side’s lead.
Glasgow City fell to second place as they were held to a goalless draw at Oriam by Hearts, with the hosts remaining third.
Emma Brownlie and Bayley Hutchinson went close for Eva Olid’s side and Jackie Richards came close to turning in a late cross.
Leanne Ross thought her side had taken the lead but Nicole Kozlova’s bundled-in finish was ruled out for a handball by Katie Lockwood as the ball made its way across goal.
Both sides lacked the decisive bit of quality in the final third, despite sustained periods of attacking possession.
Elsewhere, Partick Thistle drew with Spartans at Petershill Park in another fiercely contested match.
Hannah Jordan put the visitors ahead in the opening stages before Carla Boyce levelled for Thistle before the interval.
The hosts notched up nine shots on target but Jack Beesley’s side stood resolute as the game finished level.