The visitors looked decidedly nervy from the off.
It was player-of-the-match Kiery Horne who took the game by the scruff of the neck and started some strong, attacking runs from the wing.
Josie Rice weaved her way into the D and earned a penalty corner for Garstang and fellow midfielder Lyndsey Hayes neatly converted.
It was 2-0 to Garstang soon after when Rice played a through ball from midfield to Rebecca Worthington, who forced the keeper wide and scored the goal of the season so far from the right into the roof of the net.
The third goal came after pressure in the D, with a reverse-stick finish from Rice.
The tables turned when South Lakes won a set play and a Garstang foot on the line earned a penalty flick, South Lakes converted in style.
Stern words from coach Dave Gee at half-time demanded more of his side.
But it was South Lakes who picked up on a Garstang mistake and broke quickly and pushed the scores closer to make it 3-2.
Horne upped the tempo once more with run after run and hard work on and off the ball.
Defender Lindsay Thornhill had some good passages of play by cutting out South Lakes attacks and making forward inroads.
She picked up the ball on the half-way line and eventually reaching the D and won a penalty corner.
Hayes made no mistake and grabbed her second, making it a final 4-2.
Garstang will need to up the tempo in this weekend’s top-of-the-table home date with Pendle 1sts.