Chop the mint leaves. Cut lemon into small wedges and remove the seeds carefully. Keep one aside for garnish.
Crush mint leaves, sugar and lemon wedges in a tall glass using a wooden spoon for lemons to release all their juice and to blend in the flavors. Crushing of mint and lemon is referred to as muddling and is generally done with a muddler.
Add ice and top up with Sprite and mix well. Garnish with lemon slices and mint leaves. Serve chilled.