Thistle took the lead early in the match before McCoy’s hat-trick, a Lizzie Arnot double and a fantastic strike from Zoe Ness saw the Light Blues secure all three points.
Malky Thomson named four changes to his side from last weekend’s Old Firm victory, Janni Arnth, Ciara Grant, Zoe Ness and Kayla McCoy all came into the starting XI with Brianna Westrup, Sam Kerr, Megan Bell and Jane Ross on the bench.
Rangers lined-up at Auchenhowie with Jenna Fife in goal and a back four of Nicola Docherty, Janni Arnth, Chantelle Swaby and Demi Vance.
Ciara Grant and Tessel Middag were holding in midfield with Brogan Hay, Zoe Ness and Lizzie Arnot infront of them providing support for striker Kayla McCoy.
It was a lively start to the game as the visitors came looking to put early pressure on Rangers.
A series of corners for Thistle saw them take the lead with just 6 minutes on the clock. Cara Mcbrearty whipped the ball into the centre of the box and Linzi Taylor managed to get a strong connection to fire beyond Jenna Fife.
Rangers looked for an instant response as Lizzie Arnot’s header was saved by Lauren McGregor before Chantelle Swaby headed over from a free-kick.
In the 13th minute Rangers were back level. A short corner taken by Lizzie Arnot was played into the path of Zoe Ness on the edge of the box.
Ness turned and fired a shot at goal which was blocked before the rebound fell to Kayla McCoy and despite the efforts of the Partick Thistle defence to clear the ball had crossed the line and the referee awarded the goal.
Rangers had the lead before the hour mark after a stunning strike from Zoe Ness. The forward picked up the ball 25-yards out and found herself in space to take a touch before curling a right-footed shot into the top corner of the net.
The Light Blues were in control at Auchenhowie and had another good opportunity to increase their advantage as Lizzie Arnot’s corner was headed towards goal before goalkeeper Lauren McGregor pushed it away but Tessel Middag's shot was over the bar.
In first-half injury time Rangers had their third goal of the afternoon. Demi Vance drove forward down the left before delivering a dangerous ball into the box. Kayla McCoy had got into a good position to find space at the back post and headed home her second of the game.
Just two minutes into the second-half, McCoy had her hat-trick. Zoe Ness fed the ball out wide to Lizzie Arnot who made a darting run down the left before picking out McCoy and she turned it behind to put Rangers 4-1 ahead.
With half an hour of the game remaining, Kirsty Howat and Megan Bell were introduced in place of Kayla McCoy and Zoe Ness.
Rachel Donaldson tried an effort for the visitors from distance but it was a comfortable save for Jenna Fife in the Rangers goal.
The Light Blues were continuing to threaten as Brogan Hay cut the ball back to Sam Kerr but her powerful strike drifted just over the bar before Hay had a low shot saved by Lauren McGregor.
Rangers were awarded a penalty on the 72nd minute as McGregor came off her line as Brogan Hay drove towards goal but took out the Gers winger and the referee pointed to the spot.
Lizzie Arnot stepped up to take the spot-kick and sent the keeper the wrong way to slot into the bottom right-hand corner.
Rangers were searching for more goals and made it 6-1 with some lovely build-up play. Nicola Docherty found the run of Sam Kerr on the right and she delivered an inviting ball into the box.
Kirsty Howat was at full stretch but couldn’t get a touch on the ball however Lizzie Arnot had made an advancing run into the far side of the box and placed a low shot into the bottom corner of the net.
Shortly after, Kirsty Howat was denied from close range after a good block from Thistle goalkeeper McGregor before Megan Bell’s looping shot from distance was denied by the crossbar.
Into the final 10 minutes of the match Rangers were continuing to pile on the pressure as Chantelle Swaby’s shot was matched with a good save from McGregor.
Bell came close again as the Light Blues drove forward on another attack but the Northern Ireland international was again denied by the crossbar.
RANGERS: Fife, Docherty, Arnth, Swaby, Vance, Grant (Kerr, 46), Middag, Hay, Ness (Bell, 62), Arnot (Jordan, 87), McCoy (Howat, 62)
Subs: Cunningham, Ross, Westrup.
Partick Thistle: McGregor, Murphy, McCulloch, Falconer, Fleming, Docherty, McGlashan, Mcbrearty, Taylor, Macdonald (Bulloch, 57), Donaldson.
Subs: Grant, McCann, Fisher, Dalziel, Hammill, Anderson.