A federal judge issued a landmark ruling last year, saying that Google had become a monopolist in internet search. But in a hearing that began last week to figure out how to fix the problem, the emphasis has frequently landed on a different technology, artificial intelligence.

In U.S. District Court in Washington last week, a Justice Department lawyer argued that Google could use its search monopoly to become the dominant player in A.I. Google executives disclosed internal discussions about expanding the reach of Gemini, the company’s A.I. chatbot. And executives at rival A.I. companies said that Google’s power was an obstacle to their success.

On Wednesday, the first substantial question posed to Google’s chief executive, Sundar Pichai, after he took the stand was also about A.I. Throughout his 90-minute testimony, the subject came up more than two dozen times.

“I think it’s one of the most dynamic moments in the industry,” said Mr. Pichai. “I’ve seen users’ home screens with, like, seven to nine applications of chatbots which they are trying and playing and training with.”

An antitrust lawsuit about the past has effectively turned into a fight about the future, as the government and Google face off over proposed changes to the tech giant’s business that could shift the course of the A.I. race.

For more than 20 years, Google’s search engine dominated the way people got answers online. Now the federal court is in essence grappling with whether the Silicon Valley giant will dominate the next era of how people get information on the internet, as consumers turn to a new crop of A.I. chatbots to answer questions, find solutions to their problems and learn about the world.