Front-running Cambiocorsa extended her winning streak to five in Friday's $134,125 Irish O'Brien on Santa Anita's hillside turf course, but the gray 4-year-old filly was fully extended to repel Somethinaboutlaura by a head in the St. Patrick's Day feature for California-breds.It was the fourth victory at the current Santa Anita meet for Leatherman Racing's course specialist, unbeaten in five previous starts over Santa Anita's downhill turf. Ridden by Jon Court, the 3-5 favorite Cambiorcorsa traversed the about 6 ½ furlongs in a smart 1:12 after customarily setting the pace while having to discourage an early challenge by Sterling Cat.Sterling Cat, who faded to last in the field of six, may have softened up Cambiocorsa after fractions of :21 3/5 and :42 4/5, but the winner retained enough determination to hold off the rally of 5-2 second choice Somethinaboutlaura and jockey Alex Solis."She had to work," winning trainer Doug O'Neill said afterward. "She's a special filly." In gaining her sixth win in 11 career starts, Cambiocorsa, high weighted at 122 pounds, paid $3.20, $2.40, and $2.10. She earned $80,475 to expand her career total to $292,955. Cambiocorsa's heavy favoritism led to a minus show pool of $10,914.30.Somethinaboutlaura, racing on the hillside turf course for the first time, responded to a change of styles by Solis after racing on or near the lead in most of her previous starts. She paid $2.40 and $2.10 after breaking last. Cyber Slew, who finished four lengths behind the runner-up while ridden by Garrett Gomez, paid $2.10 to show.