Trainer Robertino Diodoro reached a milestone of 3,000 wins on Saturday when Arthurian led throughout to capture the second race at Oaklawn Park in Hot Springs, Ark.   Arthurian was the first starter on the day for Diodoro, a 47-year-old native of Calgary, Alberta, Canada, who also is racing at Turf Paradise, Delta Downs and Sam Houston Race Park. He won his first race on Aug. 2, 1995 at Northlands Park, according to records from Daily Racing Form.   “The owners have a big part of it,” Diodoro said of the milestone. “One thing I’m really grateful for is reaching 3,000 with guys who were with me for the first 100.”   Diodoro said listed owners he had when starting out in Canada that have continued to support him since his operation largely moved to the United States.   :: DRF New Year Sale: Save up to 50% on handicapping essentials - DRF Past Performances, Clocker Reports, and more! Diodoro’s parents, Tino and Linda Diodoro, made the trip from Calgary to be with their son in the march up to the milestone. They were in the winner’s circle Saturday, along with a large group of owners, stable staff, friends and fans. Diodoro is the current leading trainer at Oaklawn.   Arthurian ($3.60) moved to the lead soon after the start of the second race, which was a $10,000 claiming sprint at six furlongs. He set fractions of 21.97 seconds for the opening quarter and 45.67 seconds for the half-mile before going on to win on a fast track in 1:10.59. Cristian Torres was aboard for winning owners Heath Aaron Campbell and Sheena Campbell.   “I have good owners, which equals good horses and good help,” Diodoro said. “It’s a team.”   Diodoro has won a total of 3,020 races in his career, but some were with Thoroughbreds in “hook races” against Quarter Horses. All told, the barn has had 14,378 starters in Thoroughbred races, for stable earnings of more than $60 million. Diodoro has won graded stakes with such runners as Lone Rock, Dream Lith, Keepmeinmind, Inside Straight, Broadway Empire and Sky Promise.   :: Want to learn more about handicapping and wagering? Check out DRF's Handicapping 101 and Wagering 101 pages.