Victor Korchnoi's psychological tricks backfired yesterday and the self-exiled Russian grandmaster lost the 14th game of his chess match with Boris Spassky in Belgrade. Yugoslavia. It was the fourth defeat in a row for Korchnoi, who once enjoyed a commanding four-game lead. The match score is now 7 1/2 to 6 1/2 in his favor, with 10 1/2 points needed to win.

In an apparent effort to unsettle his opponent, Korchnoi arrived late for the beginning of game 14, strolled casually onstage, made his move and strolled off again. He also began sitting in a small cubicle rather than at the playing table between moves, imitating the behavior of Spassky which he had previously complained about. But apparently this unusual location was disorienting to him, and when he ran into time-trouble late in the first session, he may have regretted the time he had wasted at the beginning of the game.

Spassky, who has complained repeatedly about the glare of the lighting in the playing hall, came onstage today wearing a sun visor, which brought roars of laughter from the spectators.

At the height of his time-trouble, during the closing minutes of the game's first session, Korchnoi was disturbed by crowd noises and asked the match officials to draw the curtain on the theater stage which is the playing area. This was done, and the last few moves before the adjournment were played behind a curtain, with the spectators watching the progress of the match on demonstration screens.