GRAND ISLAND, Neb. - Tonight Rainbow fired his best shot when it counted, easing outside dueling rivals leaving the turn and wearing down Wham for a three-quarter-length victory in Saturday's $10,000-added Grasmick Stakes at Fonner Park.\nTonight Rainbow, ridden by Curtis Kimes, scored his fourth consecutive win in the Grasmick - and fifth overall - as the 2-5 favorite for trainer Boyd Caster. He also won this race in 2004. The 10-year-old Oklahoma-bred gelding joins Leaping Plum as a dominant fixture in this race. Leaping Plum won the race seven consecutive years, from 1995 to 2001, and picked up his eighth Grasmick win in 2003. Tonight Rainbow covered the four furlongs in 46.40 seconds over a fast track and returned $2.80 in the short field of four.\nThe win boosted Tonight Rainbow's career mark to 21-12-8 from 68 starts with earnings of more than $350,000. His career mark over Fonner Park's five-eighths-mile oval is a strong 13-1-4 from 23 starts.