Question: What Louisville event had an American Thoroughbred racehorse as it's winner in 2017?

Context paragraphs:
Invasor (horse): Invasor (foaled August 3, 2002) is a Thoroughbred racehorse bred in Argentina by Haras Clausan (Haras Santa Ines).  The winner of the 2005 Triple Crown in Uruguay, he was later purchased by Sheik Hamdan bin Rashid Al Maktoum, who paid approximately US$1.4 million for the horse.  His two biggest wins were the 2006 Breeders' Cup Classic, in which he defeated heavily favored Bernardini and highly fancied Lava Man, and the 2007 Dubai World Cup, the world's richest horse race.  He finished racing with a record of eleven wins in twelve starts and career earnings of $7,804,070.  He was voted the Eclipse Award for American Horse of the Year and led the year-end World Thoroughbred Racehorse Rankings in 2006.  In 2013 he was inducted into the National Museum of Racing and Hall of Fame in Saratoga Springs, New York.

Thomas R. McCarthy: Thomas R. McCarthy (1934 – July 21, 2016) was an American thoroughbred racehorse owner and trainer from Louisville, Kentucky, best known for the 2009 Blue Grass Stakes winner and Kentucky Derby runner, General Quarters.  From a racing family, his grandfather was a jockey in Ireland and both his father and uncle trained horses at racetracks in New England.

Manuel (horse): Manuel (1896–1900) was an American Thoroughbred racehorse that won the 1899 Kentucky Derby in what was deemed a very uneventful race.  He was foaled in Kentucky and was a bay colt sired by Bob Miles out of the mare Espanita (by Alarm).  He is related through his grandsire to 1907 Derby winner Pink Star.  Manuel was bred by George James Long at his Louisville stud farm, Bashford Manor Stable.

Camarero: Camarero (1951–1956) was a Thoroughbred racehorse that was raised and raced in Puerto Rico.  He was the winner of 73 races, including the Triple Crown of Thoroughbred Racing in Puerto Rico.  Camarero is notable for setting the current world record of the most consecutive wins for a Thoroughbred racehorse at 56 in a series of races between April 1953 and August 1955.

2017 Kentucky Derby: The 2017 Kentucky Derby (in full, the Kentucky Derby Presented by Yum!  Brands, due to sponsorship) was the 143rd running of the Kentucky Derby, and took place on Saturday, May 6, 2017.  The Kentucky Derby is a horse race held each year in Louisville, Kentucky, on the first Saturday in May, at the end of the two-week-long Kentucky Derby Festival.  It is a Grade I stakes race for three-year-old Thoroughbreds at a distance of 1+1/4 mi , and has been run at Churchill Downs racetrack since its inception in 1875.  The race was broadcast by NBC with a scheduled post time of 6:34 PM ET.  The race went off at 6:52 PM ET before a crowd of 158,070 and a television TAD of 16.5 million viewers.  The winner was the post-time favorite, Always Dreaming.

Gun Runner (horse): Gun Runner (foaled March 8, 2013) is an American Thoroughbred racehorse who has won multiple graded stakes races and is one of the top ranked racehorses of 2017.  As a three-year-old, he became an early favorite for the 2016 Kentucky Derby after winning both the Risen Star Stakes and Louisiana Derby.  Following a third place finish in the Derby, he won the Matt Winn Stakes and Clark Handicap, and was second in the Breeders' Cup Dirt Mile and Pennsylvania Derby.  As a four-year-old in 2017, he has won the Razorback Handicap, Stephen Foster Handicap, Whitney Stakes and Woodward Stakes, and finished second in the Dubai World Cup.  His performance in the Whitney earned him a rating of 127 in the August 2017 update of the World's Best Racehorse Rankings, placing him third place worldwide.

Oxbow (horse): Oxbow (foaled March 26, 2010), an American Thoroughbred racehorse, is best known for winning the second jewel in the United States Triple Crown of Thoroughbred Racing, the 2013 Preakness Stakes.  A bay colt, sired by a winner of the Breeders' Cup Classic and out of a full sister to another Breeders' Cup Classic winner, Oxbow was sold as a yearling at Keeneland for $250,000 and is owned by Brad Kelley of Calumet Farm.  He was trained by D. Wayne Lukas and was ridden in his Triple Crown races by Gary Stevens.

Cigar (horse): Cigar (April 18, 1990 – October 7, 2014), was an American Thoroughbred racehorse who, in 1995 and 1996, became the first American racehorse racing against top-class competition to win 16 consecutive races since Triple Crown winner Citation did so in 1948 and 1950.  Cigar retired as the leading money earner in Thoroughbred racing history and was later inducted into the National Museum of Racing and Hall of Fame.

The Tin Man (horse): The Tin Man (February 18, 1998 in Kentucky – 2015) was an American thoroughbred racehorse.  The gelding was sired by Affirmed, the Triple Crown of Thoroughbred Racing winner, out of the unplaced Lizzie Rolfe by Tom Rolfe, who was an exceptional racehorse but a better broodmare sire.

Always Dreaming: Always Dreaming (foaled February 25, 2014) is an American Thoroughbred racehorse.  He won the Florida Derby in his first graded stakes race appearance and then won the 2017 Kentucky Derby.

Supporting paragraphs: Always Dreaming 2017 Kentucky Derby
Answer: 2017 Kentucky Derby