The Godolphin homebred's talent is not in question but here he needed the heart to go with it in a determined effort against a stubborn foe as it was only in the final strides that he finally overcame him rival to score by a neck.
Both principals were to the fore from the get-go, where Highly Motivated established a lead, pressed on his outside by the 1-2 favourite.
They drew well clear of the others, with Highly Motivated keeping the advantage in resolute fashion for most of a thrilling stretch drive until the game Essential Quality finally asserted. It was 5½ lengths back to the third, Rombauer; battle will be rejoined in four weeks' time.
• On the same card, the Maktoum filly Malathaat (Todd Pletcher/Joel Rosario) confirmed her Kentucky Oaks credentials with victory in the G1 Ashland in the famous blue-and-white silks of the late Sheikh Hamdan's Shadwell operation.
Brad Cox (Essential Quality's trainer): "Highly Motivated was travelling really well on the inside and Javier Castellano looked very comfortable. It looked like it was going to be tough to get by and he was extremely tough. He is a good horse, who has run good numbers and likes Keeneland, so we thought that he would be our main competition.
"Essential Quality needed a good, strong race today and we got that out of him, there's no doubt about it. He is getting better all the time – not that he is bad or anything – but he is a colt who is maturing all the time mentally and physically. I thought he ran a huge race today and he is a tough horse.
"He has shown us an unbelievable amount of stamina. It's the one thing I keep going back to, he never gets tired. When you breeze him, it doesn't take a lot out of him. Luis said that he was a monster today and felt like he never really got to the bottom of the horse. I think the further, the better for him. I am very optimistic about the opportunity we are going to have in four weeks and I am looking forward to the first Saturday in May."
Luis Saez (Essential Quality's jockey): "When we came to the stretch, Javier's horse was really fighting and I thought for a second that we weren't going to get it but I always have a feeling with Essential Quality. He is a nice horse and, no matter how fast or slow the pace, he always wants to be the first on the wire. He came to the stretch, he fought and he got by. What a big heart this horse has. In that type of moment, we try to do anything and he finally gave me that last try. He is a fighting horse and always in a battle."
Javier Castellano (Highly Motivated's jockey): "He ran a huge race. I got beat, finished second, but I'm so proud of my horse and the way he did it today. Easy fractions on the lead, he galloped along – that's the first time he did two turns. We tested him a little bit to see how far he could go and he did it. He tried with one of the best horses in the country."