The Brazilian lost his mother on Sunday but having decided to play on, scored a brace to help Jazira move to second.
They trail Al Ain by four points, but the win keeps Jazira in touching distance near the season's mid-point.
Oliveira came off to a standing ovation for a performance in which, for vast tracts, he was understandably a peripheral figure. After scoring his eighth goal of the season at the end of the first half, amid a prolonged spell of Baniyas domination, he raised his arms to the sky, in understated celebration and appeared to shed some tears.
He missed a penalty early in the second half, his effort grazing the post, but an adept left-footed strike from outside the area in the 76th minute sealed the victory, extending Jazira's unbeaten run to eight games. Ten minutes later he was substituted, to a rousing ovation.
Baniyas, third before the game, will wonder how the scoreline came to look so comprehensive, especially after looking more coherent in the first half.
"We're very happy because we beat a very strong team and we're now second," Paulo Bonamigo, the Jazira coach, said. "We had difficulties in the first half. They had better possession but we did the most important thing, which was to score."
Nick Carle and Mohammad Zidan were at the centre of much of the visitors' work, with Adnan Al Beloshi and Ahmed Ali sprightly outlets on either side.
Zidan, in fact, should have put the visitors ahead after 14 minutes, blazing over a presentable opportunity from 12 yards after a free kick from the right.
Ten minutes later his own free kick required a smart save from Ali Kasheif and five minutes before half time, an elegantly curled effort from just outside the box flew inches wide.
It did not look like it might be costly, so assured were Baniyas, but Oliveira made the miss feel acute soon after.
Unlike Baniyas' more deliberate and considered build-up, Jazira were direct but disparate.
Their approach reaped reward after 43 minutes though, as Ibrahim Diaky broke down the right, crossed deep for Ali Makhbout to head back with Oliveira arriving for an expert finish from near the penalty spot.
"In first half, we were really in the game, we created good chances but when you don't take those against a team like Jazira they will always be dangerous with the quality of players up front," Carle said later.
A frantic start to the second half only added to the scoreline's temporariness. Senghor muscled his way through into the box, only for Kasheif to pull off a fine save.
A minute later Makhbout was brought down inside the box; Oliveira looked hesitant and duly missed.
But Makhbout was the game-changer, running tirelessly across the lines in the first half and his reward came nearly half an hour into the second.
Jazira had tightened up, linking play better and, as Baniyas pushed forward for an equaliser, they countered.
An exquisitely clipped ball from Matias Delgado saw Makhbout through, applying an appropriately delicate lobbed finish.
Oliveira, expected to fly out early this morning to be with his family, looked drained afterwards but praised Makhbout's display.
"I did my job today. I thank everyone for their support. The situation is not so good, but life continues. It was very important to win today because we were not far out of being second.
"Makhbout's been helping me for a long time and I think he will be the best striker in the UAE."
Jozef Chovanec, the Baniyas coach, was left to rue a second successive 3-0 loss and concerns that his side might not be up to it against the stronger sides. "We created chances but couldn't score, like last week. When you have good players up front you will get goals."
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