The Rich Ricci-owned eight-year-old turned in a most professional performance on Friday evening when he easily accounted for Ted Veale by 13 lengths in the Budweiser Race over a mile and three-quarters.
Renneti is a Grade Two winner over hurdles but he is likely to remain on the Flat for now.
Mullins said: "He's a horse that has his own mind but after all that rain he loved the ground.
"Maybe a lot of the other horses didn't act on it but our fellow loved it.
"He does enjoy his racing out of stalls and we'll probably try to stick to that.
"He could go for the Long Distance Cup on Champions Day at Ascot."