Felipe Massa says he had no regrets about ignoring orders at the Malaysian Grand Prix on Sunday.
The Brazilian was instructed to let Williams team-mate Valtteri Bottas overtake in the closing stages so the Finn could challenge Jenson Button's McLaren for sixth place.
But Massa insisted he was "very close" to Button and had the " opportunity to gain more positions".
He added: "I will fight for my career in the way I want to."
Team orders are a sensitive subject for Massa.
He was often asked to play a supporting role to Fernando Alonso at Ferrari, most notably at the German Grand Prix in 2010, when he was ordered to hand the lead to the Spaniard,
Team orders were banned at the time but are now in force again.
"I don't regret anything," said Massa after Sunday's race. "I believe it was the right thing to do."
Bottas felt the team missed the chance to accrue more points as a result of Massa's decision.
"We need to learn from today for the future," said the Finn, who had obeyed an order earlier in the race to stay behind Massa while he tried to pass Kevin Magnussen's McLaren.
Rod Nelson, chief test and support engineer at Williams, insisted Massa's actions were "no big deal".
"Felipe was running fairly high temperatures on his engine and we were a little concerned about it," said Nelson.
"We felt Valtteri had quite a good chance of getting past Button because his tyres were five laps younger. Felipe's tyres were a little bit older.
"If he hadn't achieved that within two or three laps, we'd have swapped our drivers over again. It's no big deal."
He added: "It's not team orders, it's a strategic decision based on the relative performance of the cars.
"We don't want to put one driver down and one driver up. We don't run like that at Williams. We'll sit down with both drivers and discuss the situation and what we expect."