Baritone Richard Stilwell stepped smoothly into the title role of the Washington Opera's "Don Giovanni" last night. If anyone in the capacity audience was disappointed at the absence of Renato Bruson, who began the opera's run on Oct. 29 and sang the first four performances, there was no sign of it in the applause throughout the evening. The Washington Opera explained that Bruson had to cancel his last two performances "because of a conflict of dates with a performance in Trieste." It did not explain whether this conflict was known when the engagement began, in which case audiences should have been informed ahead of time.

But it did not seem to matter much last night. Stilwell is a favorite in Washington, where he sang in last year's "Merry Widow" and has also sung in such operas as "La Bohe me," "Madama Butterfly" and "Il Ritorno di Ulisse." Last night's performance showed why; he is a thoroughly dedicated and skilled professional. He took the lead role of a production already settled into its style and pace with practically no perceptible problems. He quickly mastered the production's established routines, maintained the standard level of quality and even improved marginally on his predecessor in some small details. The worst technical problem of the evening came when he had trouble with the fastening on his cloak while taking it off, and that was barely noticeable.

Stilwell is quite a different performer from Bruson; to summarize, he is a bit less suave vocally and a bit more vigorous dramatically. In "Don Giovanni," this means that he is less seductive in the delicate seranade but more powerful in the dashing champagne aria.

In the climatic duet, "La ci darem," he added a degree of pressure where Bruson had relied more on oily persuasion -- but his interaction with soprano Faith Esham was certainly as effective. He made the violence of the first scene a bit more believable.

He deserves special credit for his smooth mastery of the tricky stage business and timing in a scene in which he isolates Masetto and disarms him, then beats him up.

Stilwell also will perform in the final matinee performance Sunday. Meanwhile, the overall production has improved somewhat since opening night in matters of timing, coordination and other technical details.