ROUNDUP : LET BOB DO IT DOES IT WELL IN WILL ROGERS.

Byline: Daily News Staff and Wire Services

Nobody outside Golden Gate Fields paid much attention to the California Derby when it was run last month, but it has turned into what handicappers call a ``key race.''

Horses from the Cal Derby have gone on to big things. Winner Pike's Place Dancer followed up with an upset victory in the Kentucky Oaks at Churchill Downs. And runner-up Let Bob Do It, in his next start, blew away Sandtrap and eight other 3-year-olds in the $111,900 Will Rogers Handicap at Hollywood Park on Saturday.

To make the Cal Derby look even better, the horse who finished 3-1/2 lengths behind Let Bob Do It in second, Nightcapper, was 10th in the Bay Area race.

Let Bob Do It, a 3-year-old gelding bred in Washington, equaled Via Lombardia's year-old Will Rogers record by running the mile on turf in 1:34. The stakes victory was the first of the Hollypark season for jockey Kent Desormeaux and trainer John Sadler.

The winner is owned by Atlantic City Racecourse boss Robert Levy, Las Vegas oddsmaker Michael Roxborough, Penn athletic director Steve Bilsky and Alex Karkenny.

Sandtrap, who came into the Will Rogers with back-to-back stakes wins, cracked under pressure from Let Bob Do It and finished fifth, behind Dr. Sardonica and Come on Get Happy.

Let Bob Do It returned $14.60 to $2 bettors for his second victory in three starts since Sadler purchased him from trainer Mike Mitchell, who had claimed him for $40,000 at Santa Anita.

Older horses star today. The morning-line maker said the $125,000 Inglewood Handicap is a tight call between 7-5 Fastness and 8-5 Tychonic, with Strub Stakes winner Helmsman only third choice at 2-1 as he goes back to turf and 1 1/16 miles.

Pimlico success: Nick Zito might have his problems in the Preakness, but he loves the Pimlico Special.

The New York-based trainer, winless with five Preakness runners at Pimlico in Maryland, scored his second Special victory in three tries when Pat Day rode Star Standard to a three-quarter length victory over Key of Luck the $582,000 race. Zito also won the Special in 1992, with Strike the Gold.

Star Standard covered 1 3-16 miles in 1:54 2-5 over a track that had been downgraded from fast to muddy in less than an hour after a heavy thunderstorm. The 4-year-old has run eight races on off tracks, winning three and finishing on the board in three others. None of the rest in the four-horse field had run more than once on a wet track.

Natural winner: Natural Selection, ridden by Randy Romero, led wire-to-wire and was never seriously challenged in winning the $500,000 Grade II Illinois Derby at Sportsman's Park in Chicago.

Natural Selection, breaking from the inside post position, ran the 1-1/8 miles in 1:48 3-5. Trainer Mohammed Moubarek said he will enter the colt in the Belmont Stakes on June 8.

Smooth skiing: Appealing Skier, a victim of rotten racing luck in his last start, had everything his way at Belmont Park in Elmont, N.Y., romping home a wire-to-wire winner of the $100,000 Withers for 3-year-olds.