De Oliveira and teammate Kiyoto Fujinami claimed their second title success in the space of three seasons after a thrilling finale, as their chief title rivals failed to take advantage of the opportunity presented when the #56 Nissan GT-R NISMO GT3 bizarrely shed its front-right wheel on lap 42 of 63.
Both the #10 Gainer Nissan (Riki Okusa) and #52 Saitama Toyopet Toyota (Kohta Kawaai) crews had chances to steal the title away from Kondo, but in the end neither could hang on to the positions they needed to overturn the points deficit.
The Gainer Nissan driven by Ryuichiro Tomita lost the fifth place it needed for Okusa to win the title at the start of the last lap, as he allowed the JLOC Lamborghini of Takashi Kogure to slip past for fifth.
De Oliveira crossed the line in 19th place, and had no idea that he and Fujinami had in fact done enough to be crowned champions until being informed by engineer Shinichi Yonebayashi via team radio.
"It was a bit of a roller-coaster with the things that happened to us," reflected de Oliveira, who had been running fourth at the time of losing his wheel. "It was out of my hands all of a sudden with that trouble.
"I just tried to get back to the pits and I was hoping there would be another safety car or something to give us a chance to recover somehow. You just try to believe.
"I didn’t have communication with the team for the last 20 laps, I didn’t know the situation in the championship. When I took the finish, the engineer told me we finished P20… and then three seconds later, ‘we are champions!’
"It was strange because I didn’t know the situation, not even on the last lap. I was in tears, I was crying. Sometimes things can happen in racing, but we had a [lucky] star watching over us."
The Gainer car of Tomita, which finally finished eighth, was unable to maintain its pace due to a fuel shortage.
De Oliveira's two GT300 title successes follow a long stint as a Nissan GT500 driver which came to an abrupt conclusion at the end of the 2018 season, when he and Satoshi Motoyama were both axed by the marque.
The 41-year-old, who was also Formula Nippon champion in 2010, says he is motivated to remain in the lower division in a bid to earn more titles.
"I love SUPER GT, I love this feeling of racing, I just want to try and win many more titles if possible," said the Brazilian. "I feel like I can still drive at my best, at my peak, and I will keep pushing as long as I can."
