Saratoga Springs, NY--ď...In thoroughbred racing, the term great is an adjective held in such high esteem that itís often referred to as Ďthe G word.í Itís used sparingly, usually when remarkable performance meets historical achievement under extraordinary circumstanceÖĒ

Invasor, retired to stud last week after sustaining an injury, was a great racehorse.

Perhaps we jumped the gun back in March when we wrote that first paragraph, and Invasorís body of work, in terms of historical perspective, is still relatively small. But his record is all that remains now.

Eleven wins from 12 lifetime starts. A winner on three continents, he was Horse of the Year on the two in this hemisphere. A winner of the Uruguayan Triple Crown. Never defeated in a Grade or Group 1 race, nine in all. He was a margin horse, winning five South American starts by a combined 24 lengths, but also never lost a stretch battle. Adversity couldnít stop him, either.

What made Invasor great was his class, courage and athleticism.

He overcame a stumbling start and multiple stretch challenges before looking a late runner in the eye to win a Whitney. He was not deterred by a bobbling break, pronounced bias, the eventual 3-year-old champion, or the only handicap horse to ever sweep Californiaís storied Grade 1 trilogy and won a Breedersí Cup Classic with his ears pricking.

In the Pimlico Special, his American debut, after having crossed the Atlantic twice, he altered course, lost three lengths when his rider dropped a reign, but re-rallied to beat one of the fastest horses in training. In the Suburban, he bobbled at the start, was soundly bumped, then dominated six rivals to win by almost five.

In his 2007 debut, he clipped heels entering the stretch, nearly fell, regained his stride, then displayed a brilliant turn of foot on the rail to bust the Donn Handicap wide open. Thatís when, for me, he became a great horse.

Finally, in what would be his last start, he was used hard throughout at a considerable loss of ground and still won the Dubai World Cup. In defeating Discreet Cat, among others, he avenged his only defeat.

He was the best handicap horse I saw since Spectacular Bid, which Iím sure will engender an Ann Coulter-like response from fans of the great Cigar. Itís very difficult comparing horses from different eras for many reasons, but performance figures can be a useful measure.

ďI think Invasor was great, too, but Formal Gold and Ghostzapper were consistently faster,Ē said Cary Fotias of Equiform and HorseRaceInsider.com. ďYou could put Invasor with them on the intangibles, his innate ability and talent. But [everyone] knows how good Skip Away was and Formal Gold just killed him.Ē

After working five furlongs in :59 2/5 at Belmont Park in preparation for his Suburban Handicap title defense this Saturday, a swelling was discovered which later proved to be a fracture at the top of the sesamoid bone in his right hind leg. While not life-threatening, the decision was made to retire him to Shadwell Farm in Kentucky.

But his issues might have started sooner. A veteran exercise rider from another barn told me during Belmont week that she didnít think Invasor was doing well. I referred to this conversation on the Capital OTB television network the following weekend.

ďHis action looked terrible,Ē the exercise rider said. ďHe definitely has a problem somewhere.Ē

ďHeís being pointed to the Suburban,Ē I said.

ďWhenís that?Ē she asked.

ďEnd of the month.Ē

ďI doubt heíll make it,Ē she concluded.

Make of this conversation what you will. The racetrack is a tough place, rife with jealousy. But this was a person with no axe to grind with Invasor or his connections. Indeed, they might not even know of each otherís existence.

Racing at the highest levels of the sport takes its toll more often than not. Todayís successful thoroughbred also must travel extensively. Invasor crossed the Atlantic a total of four times. His last race was an enervating effort in the Dubai World Cup. That run followed the Donn, a race in which he nearly fell.

Either race could have been the beginning of the end of Invasorís racing career. But the Dubai World Cup is a most demanding event held in a desert. It gets so hot in the United Arab Emirates that racing must be conducted at night. The race is so stressful that many American-based horses werenít the same after competing in the World Cup.

And what are the chances Invasorís connections would admit the problem surfaced in his last race? Owner Sheikh Hamdanís brother, Sheikh Mohammed bin Rashid al Maktoum, owns Nad Al Sheba Race Course. The fallout from such negative publicity certainly wouldnít inspire other American owners to ship their horses Dubai, no matter how big the purse money.

But at least Sheikh Hamdan still has Invasor and he can look forward to racing, or selling, his offspring. And suddenly this yearís BreedersĎ Cup Classic becomes only a great betting race instead of a showdown between a defending Horse of the Year and the three-year-old class of 2007 that would have pushed him to the limit again.

Make no mistake. The loss of Invasor to the breeding shed is a huge blow for the sport, one only exacerbated by the premature retirement of otherwise healthy thoroughbreds worth more at stud than on the racetrack. Even the great ones like Invasor