Willie Mullins’ charge dominated the race and had too much for odds-on favourite De Bon Coeur, who was second in Auteuil.
It marked a fifth win in the race for Mullins, and Townend was delighted with the performance.
He said: ‘That went as smooth as it can.
She got a little bit keen the first time around when Melon was running very free beside us, but the second he went by us, she dropped the bridle again.
‘She travelled everywhere and picked up really nicely off the bend.
She saw out the trip very well in the end.’