A thoroughbred miss owned by the U.S. Ambassador to Switzerland scaled new heights yesterday as Marvin L. Warner's Itsamaza captured the $28,100 Marlboro Nursery Stakes which featured Bowie's opening-day program.

A crowd of 8,176 bet $918.320 on the nine-race card, including $111,968 on the Marlboro. Quite a bit of that total involved Itsamaza. The chestnut filly returned $8.20 as the second choice in the field of nine and she combed with Danger Bearing for a $22.40 payoff on the 8-9 exacta combination.

"This is the filly's first stakes victory," trainer Arthur Hoffman noted shortly after the winner's circle ceremonies. "Today was the first time we've tried her in company this tough or at a distance this long (seven furlongs) but that margin she won by (eight lengths) speaks for itself."

Warner, who was appointed to his ambassadorial post only recently, paid nearly $50,000 for Itsamaza. She was bred and owned previously by the Hickoery Tree Farm in Middlebug, Va.

That price apeared to have been a trifle high early in Itsamaza's career. The daugther of Limit To Reason ran with a $40,000 claiming tag in her first start, June 17 at Belmont Park and was available for claiming again in New York, for $45,000, on July 20.

Itsamaza broke her maiden by eight lengths on her second claiming appearance, then won two allowance dashes at Delaware Park before being pointed for the Nursery. On Aug. 26 at Delaware she downed Danger Bearing by a nose. Yesterday danger Bearing pressed Itsamaza's pace for a half-mile (in 146 1/5), then concentrated on saving second money by neck over Treat.

Mesa Warrant was favored at 2 to 1. She was the only stakes winner in the lineup, having scored in the Blue Hen this summer at Delaware. But Mesa Warrant never was a serious factor, winding up seventh, nearly 13 lengths behind Itsamaza.

Jimmy Moseley rode the winner, "I had to tap her (with the whip) only once," he said. "That was at the top of the stretch. From there on, I kept urging her a little. I didn't want to take any chances, this being the first time she'd been at Bowie."

Itsamaza is stabled at the Meadowlands, the new track in East Rutherford, N.J. near New york City.

"She's going home, and I guess we'll try her in some of the big-money stakes in New York, like the Frizette," Hoffman said. "I'm not saying she belongs there, but it's obvious we didn't know she was this good when she started running her this summer. We brought her along slowly. Now she's won four in a row, even though she paddles in front (makes a circular motion with her feet while running).

"There isn't a 2-year-old filly in the country who really stands out," the slender young trainer continued. "With that being the case, we shouldn't be afraid to try her against anyone." We might just take a shot.

Hoffman believes young 2-year-olds are capable of improving sharply in a short period of time.

They can change almost overnight," he remarked. "I remember being in California one winter and there was a 2-year-old out there who couldn't win for losing. He lost his first five races. The next spring, at 3. he won the Kentucky Derby. Name was Cannonade.

Bowie's beautication program for its late-summer meeting consisted of only one visible change. The segments of the infield tote board where the odds are flashed now are painted a slashing, deep red color in contrast to the dark green on the other parts of the board. CAPTION:

Picture, Go Bet (8) begins drive past leader Makeashane to win first trace on opening day at Bowie, by Richard Darcey - The Washington Post; Picture 2, Eugene Eseman rides Little Switch to victory over Commanding Kathy in Bowie's fourth race. By Richard Darcey - The Washington Post