SEASON OPENER : ROTTERDAM’S PHILHARMONIC AT SEGERSTROM

In the 10 years since the Rotterdam Philharmonic last visited Southern California, the Dutch orchestra’s profile has come into focus, solidified and expanded. James Conlon, the 37-year-old U.S. conductor, is now in his fifth season as music director, with a contract extending through 1991; and what had been described as a bland orchestra has become a brilliant one.

In Segerstrom Hall at the Orange County Performing Arts Center Thursday night, the Rotterdam ensemble gave an engrossing and ear-filling performance devoted to three sometimes-neglected works: Bohuslav Martinu’s “Les Fresques de Piero della Francesca,” Tchaikovsky’s Second Piano Concerto and Rachmaninoff’s Symphonic Dances.

Credit Conlon--energetic but controlled, looking always to the longer line but ever caressing the details--with extracting the real juice of these lush and expansive pieces. Credit his international orchestra--one third of its members come from 16 nations other than the Netherlands--with the virtuosity and panache to illuminate the conductor’s insights.

Conlon’s ingenuity put the Czechoslovakian composer’s showy suite first on the program, and he challenged his listeners immediately with pungent harmonies, extravagantly colorful orchestral writing and exotic instrumental effects. A masterful stroke, handsomely executed.

At the other end of the evening, Rachmaninoff’s wondrous Symphonic Dances emerged even more incandescent--but never strident--in a performance that seemed to move spontaneously but inexorably from thought to thought.

And, in the middle of the program, Bella Davidovich brought her customary elegance, impassioned delivery and strength of utterance to a grandiose reading of Tchaikovsky’s stepchild piano concerto, the longish but irresistible Second.

No concerto could have a more convincing advocate: Those reams of sixteenth-notes, octave passages and double cadenzas in the first movement have seldom sounded so important, so life and death. The less than inspired Andante, wherein violinist Gerard Hettema and cellist Michel Roche played crucial solos, emerged perfectly touching and integrated. And the finale, though lacking all the humor it contains, became the capper in an extrovert display of pianistic prowess and gentility.

This event opened the 34th season of concerts sponsored by the Orange County Philharmonic Society.