Oliveira, who finished fourth, was just 0.123 of a second behind race winner Alex Rins's Honda. They had left the rest of the pack trailing in their battle to the flag.
Oliveira was up to fifth by the mid-point of the race, with a group of more than 15 bikes jostling for position. On lap 11 of the 17-lap race he took the lead.
From there the elite of the smallest class battled over every inch of the 5.9-km Silverstone circuit, crossing the line all but four abreast.
"Emotions are difficult after a race like this, as I can't help but be very, very disappointed for me and the team to have missed out on the podium. However, it was a great race - a lot of fun. The bike was going well and we were right there, so I can be happy for that," Oliveira said.