LOS ALAMITOS, Calif. - The $189,200 Southern California Derby at Los Alamitos on Sunday is the final major race of the year at the famed Quarter Horse track. From trainer Scott Willoughby's perspective, the Southern California Derby is the start of the 2009 season.\nWilloughby is convinced that Thinking First, the colt he starts in the 400-yard race, can not only win on Sunday, but show that he will play a major role in the older horse division next year.\n"I think he'll be one of our best horses next year," Willoughby said.\nThinking First enters the Southern California Derby following a second in a division of the time trials on Nov. 28. Thinking First was beaten a head in that race by fellow qualifier Tsunami Splash despite lugging to the inside under jockey Jeff Jerman.\n"He should have won the race," Willoughby said. "Jeff picked his head up in the last 50 yards to keep him from going in. I think he'll improve at least a length off that race."\nThinking First, owned by Los Alamitos Race Course owner Ed Allred, has raced against some of the nation's toughest Quarter Horses. In August, he was third to the star 3-year-old One Famous Eagle in the Golden State Derby. A month later, Thinking First was fourth against older horses in the Go Man Go Handicap.\nAfter the Go Man Go, Willoughby discovered that Thinking First was suffering a foot abscess.\n"Everything seems to be 100 percent now," he said. "It looks like we've worked through that."\nNone of the 10 qualifiers has any major stakes victories this year - at least ones they were allowed to keep. Fighter on Fire finished first in the El Primero Del Ano Derby in April, but was later disqualified from purse money for a clenbuterol positive.\nThe field does include several prominent 3-year-olds. Decati was third in the All American Derby at Ruidoso Downs. My Lady First was third in two derbies at Los Alamitos this year, and Short Czech was second in the Governor's Cup Derby during the summer. Terrific Energy, who is making his stakes debut on Sunday, set the fastest qualifying time of 19.47 seconds in the trials.\nLeading trainer Paul Jones starts Tsunami Splash and Tailgunner Tom, who won a $134,000 race for maidens in March.