Los Angeles Dodger rookie Fernando Valenzuela, who has excited the baseball world with his near flawless pitching, suffered his first defeat of his rookie year tonight as the Philadelphia Phillies downed the Dodgers, 4-0, before 52,439.

Valenzuela failed in his attempt to win his ninth straight game, leaving for pinch hitter Rick Monday in the seventh inning with the Dodgers trailing, 4-0.

"If I win a game I am happy and if I lose, I'm not gonna cry," he said through an interpreter.

Valenzuela had equaled the feat of Dave (Boo) Ferriss by winning his eighth successive start last Thursday night when the Dodgers beat Montreal, 3-2. Ferriss accomplished the feat in 1945, and it is believed that no other rookier major leaguer has had a better start.

Valenzuela said he felt no extra pressure from the presence of his parents, flown in by the Dodgers from their home in Etchohuaquila, Mexico.

After Valenzuela, a 20-year-old left-hander, retired the first two batters of the game, Mike Schmidt hit his 12th home run of the season. The Phillies got three more runs in the fourth inning on RBI singles by Keith Moreland and Gary Matthews and a sacrifice fly by Garry Maddox.

Valenzuela allowed only three hits in his seven innings. He walked two and struck out six. His earned run average is now 0.91, as the four earned runs scored by the Phillies equaled the total Valenzuela had allowed in his first eight starts of the year.

The loss also snapped the Dodgers' seven-game winning streak.