Runaway winner of the Metropolitan Handicap (G1) is the only winner of that race in the last quarter century to have also captured a grade one event at two. From the Giant’s Causeway branch of Storm Cat’s sire line, he is out of juvenile stakes winning Dixie Union mare from the immediate family of Champion Stellar Wind.
Like Giant’s Causeway, Mor Spirit has done very well with M. Prospector line mares, getting multiple graded stakes winner Eskenformoney out of a mare by Not For Love, as wel as stakes winners from daughters of Lemon Drop Kid, Carson City (sire of City Zip), Strong Hope (by Grand Slam) and Mr. Greeley – both from the Gone West line, which also suggests Elusive Quality, Speightstown and Proud Citizen – Thunder Gulch, Hawk Wing (by Woodman) and Victory Gallop (by Cryptoclearance, who might also be brought in through Candy Ride). Looking at the Giant’s Causeway line in general, we might also consider Northern Afleet and his son, Afleet; Seeking the Gold, sire of Mutakddim, Petionville and Cape Town; Street Cry and sons; Smart Strike; Distorted Humor and Fusaichi Pegasus.
The Fappiano branch has enjoyed success under Giant’s Causeway through Unbridled's Song (by Unbridled), Quiet American (grandsire of Midnight Lute, who could be interesting here), Rubiano and Roy. Unbridled and Unbridled's Song could also be introduced through Broken Vow, Empire Maker, Grindstone, Birdstone, Rockport Harbor, First Defence, Old Fashioned, Half Ours, Dunkirk, Even The Score and Songandaprayer.
Eskendereya has graded winner Isabella Sings out of a mare from the Nijinsky II which might be introduced through Royal Academy and Sky Classic. From the Deputy Minister branch of Northern Dancer, there are Eskendereya stakes winners out of mares by Deputy Minister himself and his son, Dehere, suggesting crossing over Awesome Again (sire of Ghostzapper), Silver Deputy and Touch Gold.
There is an Eskendereya stakes winner out of a mare by Dayjur, a son of Danzig, a strain that might be introduced through Belong To Me, Polish Numbers, Langfuhr, War Chant, Hard Spun, Exchange Rate and War Front. From the Sadler’s Wells line there is a stakes winner out of a mare by Kitten’s Joy (by El Prado, also sire of Medaglia d’Oro and Artie Schiller), and there is also a stakes winner out of a mare by Unusual Heat, who is by Sadler’s Wells’ three-quarters brother, Nureyev (also available through Stravinsky and Theatrical).
Mor Spirit is out of a mare by Seattle Slew, and crossing back over that line through A.P. Indy and sons such as Pulpit (sire of Tapit and Sky Mesa), Jump Start, Malibu Moon, Mineshaft, Congrats and Flatter.
Out of mares from the Halo line, Giant's Causeway and sons have three stakes winners, one grade one from daughters of More Than Ready, and Halo could also be introduced through Devil's Bag and Saint Ballado whose sister, Champion Glorious Song, is in the pedigree of Giant’s Causeway.
There is an Eskendereya stakes winner out of a mare by Indian Charlie (sire of Uncle Mo) by In Excess, who is by Siberian Express, also sire of Siberian Summer, the broodmare sire of two Giant’s Causeway classic performers. This is branch of the Caro line, and Maria's Mon who is out of a Caro mare, and he has worked under Giant's Causeway. His son, Monarchos, is also broodmare sire of a Giant's Causeway line stakes winner and might be interesting here, while Super Saver mares also appeal.
The Giant's Causeway line has done well with a number of Relaunch line broodmare sires, including Honour and Glory (sire of Put It Back), Cee's Tizzy, Tiznow and Bertrando (sire of Officer).