Ectot came out best in a duel with Karakontie to enhance his Classic claims in the Prix de Fontainebleau at Longchamp.
Winner of his final four starts as a juvenile having been beaten by Karakontie when the pair made their debuts at Compiegne in July, the Elie Lellouche-trained Ectot was recently added to the Investec Derby field at a cost of £8,000.
Racing immediately behind what looked a genuine pace set by stablemate Serans, the Gregory Benoist-ridden Ectot took over around two furlongs out and quickened smartly with Karakontie giving chase.
Benoist's mount was always holding the upper hand, however, and finished snugly in front of the Prix Jean-Luc Lagardere winner.
Coral cut Ectot to 16-1 from 25-1 for the Qipco 2000 Guineas at Newmarket on May 3, but he appears more likely to stay at home for a tilt at the French equivalent, the Poule d'Essai des Poulains.
Benoist said: "I couldn't wait to ride Ectot in a race (again).
"We didn't want to suffer a slowly-run race and that is why we put in a leader.
"He delivered a beautiful final straight. He has a lot of speed and certainly seems to have grown up during the winter.
"I hope he can take me to new heights."
Earlier, Lesstalk In Paris led all the way for victory in a messy renewal of the Prix de la Grotte.
The Jean-Claude Rouget-trained filly was reversing Prix Marcel Boussac running with Indonesienne, who had to settle for third on this occasion with Straight Thinking in second.
A slow time reflected the pedestrian pace from the outset, although the winner showed a good attitude in keeping her rivals at bay and is set to run next in the Poule d'Essai des Pouliches - the French 1000 Guineas.
Winning jockey Christophe Soumillon said: "You never know how prep races turn out.
"She came quickly out of the stalls and I was struggling to hold on to her.
"We wanted her to learn how to breathe by keeping her in behind the other, but I didn't have a choice.
"I hope that she will be able to recover in time (for the French Guineas), because even if we didn't go too fast, it is still a big effort."