The fight went to the scorecards after going the full three round distance but it was Adesanya that got the win via unanimous decision.
The most risky moment for Adesanya came in the third round, when Silva launched into a flying knee attempt.
When the judges returned their scorecards, Adesanya earned the victory with a 30-27, 30-27, 29-28 unanimous decision to move to 16-0 in his mixed martial arts career.
Late in the first round, Adesanya turned the tables on Silva by showcasing a flashy array of strikes and then putting one hand behind his back and inviting the former champion to come after him like he was Neo in "The Matrix".
Robert Whittaker has not fought since June of 2018, when he engaged in his second five-round war with the behemoth Yoel Romero.
Silva said it was the equivalent of facing Michael Jordan in basketball. "I showed up, traveled thousands and thousands of miles from home, made the weight".
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But a patient Adesanya, who like his opponent, also displayed some showboating, dominated the third, peppering the Brazilian's face with punches as the veteran sometimes held his hands low.
Gastelum, a former victor of The Ultimate Fighter, conducted interviews after the news with a title belt.
"But, hey, Player one has the controller, so I showed up".
Whittaker's manager Titus Day said the champion first reported some issues around 6pm on Saturday. I don't care. Kelvin or Rob, whoever it is I don't care.
But despite Gastelum's claims to the belt, UFC president Dana White told reporters that because of the relatively short recovery time needed following Whittaker's operation, the Australian would not be stripped of his world title. "They think he's had it for a while and it's been popping in and out", White said of Whittaker.
In his post-fight interview, Adesanya said fighting Silva was like fighting his idol. This is my life. "It was a fun fight to watch, very fun, with two guys who are incredibly talented". I'm fighting for the belt next that's all I know.