When he careered away with the Irish Derby on the last day of June, Zagreb put six lengths between himself and a field that included the narrowly beaten runners-up in the Derby at Epsom and the Prix du Jockey-Club at Chantilly, Dushyantor and Polaris Flight.
The riders of that pair, Pat Eddery and John Reid, were striving so strenuously in pursuit that they did not have time to see which way Zagreb went. But Willie Carson, resigned to ninth place on Alhaarth, got a view, a somewhat distant view, of greatness.
"I'm telling you he's the best three-year-old in Europe," Carson said after catching his breath. "That was some performance."
When the official handicappers did their sums the next day they came to the same conclusion, placing Zagreb ahead of the Epsom and Chantilly winners, Shaamit and Ragmar, in their ledgers.
The rich summer pickings have gone now, fallen to others without Zagreb laying down a challenge. But the rains of autumn announce his return and he will be back on the racecourse a fortnight tomorrow, defending the Champion Stakes for Ireland at Leopardstown and then taking on Europe's elite in the Prix de l'Arc de Triomphe on 6 October.
Many trainers would not have been capable of making the decision to keep a horse of Zagreb's talent away from the track during such a lucrative period of the season; the pressure to order an immediate strike with a horse in such devastating form proving too great a lure.
Fortunately for Zagreb he is in the care of Dermot Weld, who, having saddled winners on four continents, is not lacking in the self confidence required to resist temptation. "It was an easy decision really," he said this week. "He was a big, weak, and immature horse. Now, when a lot of horses are past their peak he'll just be reaching his."
Weld was speaking from a hotel in Killarney, his base for a week of racing at Tralee, one of the most popular stopping-off points on Ireland's circuit of festivals. Perhaps it was the serenity of the scenery, perhaps it was just the self-possession that comes with a quarter of a century of success in a profession, but Weld simply exuded confidence in Zagreb.
"I'm very happy with him," Weld said. "Mick [Kinane] rode him over a mile on Tuesday and he worked right away from the others. It was his first piece of work on grass since the Derby and Mick was very pleased.
"Zagreb had a very easy July. We had some warm weather and he enjoyed it. Now he's starting again, but he's very clean-winded and is easy to get fit.
"He'll go for the Irish Champion and then Longchamp. I entered him for the Arc in May and he was the only three-year-old I entered, which was significant. I knew then he had an awful lot of talent."
Zagreb has raced just three times, showing such dramatic improvement to win the Irish Derby that the curve marking his rate of progress is almost vertical. It is an awesome thought to consider for those preparing his rivals.
"He'll stay in training next year," Weld said. "It's been discussed with his owners. I'd like to think he will be much better then.
"I'm looking out on one of the most beautiful scenes in the whole world, not just Ireland, the upper lake in Killarney. There's a little fishing boat away on the other side of the lake and 40 miles of mountains behind. Everything is calm and serene." Some prospect, some horse.