The Ireland striker hit a superb hat-trick to complete a Galaxy comeback against Real Saltlake and the United States international praised his ability to change the game
After going behind to a Joao Plata goal in the 53rd minute, Keane struck three times to take his tally for the season to 10 goals and Donovan explained that the Republic of Ireland captain was capable of doing it "on any given night."
"Robbie was Robbie," said the 31-year-old, who scored a hat-trick himself a week earlier. "He can do that on any given night, which is crazy to say but if we give him the ball in the right spots he's going to make those plays. He was terrific.
"His first goal really put us back in and that was all on him, he did a great job of shielding the guy and then cutting and the finish was fantastic. That's absolutely world class and there are not many players in the world that would have pulled off a play like that."
While admitting that it was "nice" to get a hat-trick, the former Tottenham Hotspur and Liverpool striker placed emphasis on securing three points for the team.
"It's always nice to score goals but the most important thing is the three points," said Keane.
"And after going a goal behind we showed a lot of character to come back and get four goals in the end because you have to win the game."
LA Galaxy's next game sees them pitted against Costa Rican side Cartagines in the opening game of the Concacaf Champions League group stage on Tuesday August 20.