Donovan entered the game in the 63rd minute and 12 minutes later met a cross from Massimo Oddo just outside the goal area. Donovan beat his marker to the ball and headed inside the near post.
VIDEO of Donovan's goal.
Italian striker Luca Toni had opened the scoring for Bayern in the first half of the game that raised $650,000 for cash-strapped Kaiserslautern.
Donovan, who is hoping to turn his loan spell into a transfer, has now produced in three of the four friendlies he's played. He scored in a 3-1 friendly win over Saudi Arabia's Al-Wehda, and notched an assist and drew a free kick that led to a goal in a 3-2 win over the UAE's Al-Jezeera SC.
Also on Monday, Bayern announced that German international striker Lukas Podolski will move to FC Cologne next summer. The German press reported that Cologne will pay a $13 million transfer fee, matching what Bayern paid to acquire him in 2006.
Podolski has been plagued by injury and illness, and is not expected to be ready when the Bundesliga returns to action Jan. 30. Bayern Munich coach Juergen Klinsmann has indicated that Donovan is his third choice at striker behind the two-man frontline of Toni and Miroslav Klose.
Donovan's first chance to see action in an official game comes Jan. 27 when Bayern meets VfB Stuttgart in the German Cup quarterfinals.
"For me, everyday is a countdown," Donovan told Bild newspaper, which praised his perfect German. "I have to show something everyday. In practice, on the bus, on the plane. It's all important. This is a once in a lifetime chance."