At 24 he is one of Formula One's younger stars, and after four inconclusive seasons in the top echelon he knows that he is expected to deliver now that he has switched to a long-term contract with Jackie Stewart's fledgling team, Stewart Grand Prix. Some saw that as a step backwards for a man who was being discussed as a potential McLaren driver in 1994, but Barrichello is convinced it is the start of something big, and his performance in qualifying 11th in the team's maiden race in Australia a fortnight ago suggests he has made a shrewd decision.
"It's the kind of opportunity that doesn't come up every day," he said, "the chance to build a new Formula One team from the ground up. I wouldn't have done it at this stage of my career if I wasn't completely confident in Jackie and Paul Stewart."
At this honeymoon stage, the former champion Stewart is equally entranced. "I've been very impressed with Rubens," he said. "He knows what he wants, and I think we have yet to see his best." But Jackie was relieved when a late improvement by Barrichello's old Nemesis, Eddie Irvine, denied him the gold Rolex watch Stewart had offered as reward for a top 10 start in Melbourne.
More than most, Barrichello needs to feel welcome in a team. In his early days at Jordan in 1993 he was part of the family, comfortably outpacing the veterans Ivan Capelli and Thierry Boutsen. In the European Grand Prix at Donington, when Senna was in such majestic form, his own performance held great promise, which is as yet unfulfilled. Then came Irvine and an internal rivalry that undermined his confidence.
Last year, paired with the more user-friendly Martin Brundle, there was still friction. And when Jordan advised him at season-end to take what options he had, it hurt. So what went wrong? What caused the rift that left him saying: "I don't want to say that Eddie [Jordan] is not professional, but Stewart is on a different level."
"I was left alone," he said. "Gary Anderson [Jordan's chief designer] was always there to support me in the first three years. But last year I felt that I was a bit apart, and my problems started. Martin went faster. I never ever said that he had better equipment than me, but I never could actually fine-tune the rest of things like he could. It was upsetting. To feel isolated was the worst thing. When you hear things going on behind you, that isn't very good.
"Jordan brought me very good things, especially bringing me into Formula One. But I definitely think that the team are in a position now because of my services as well. Eddie is very supportive when he wants to be, but he can also be very depressing. Since the middle of last year, I didn't have that support."
In the old days, Barrichello could always count on advice from Senna, and the memories still haunt him. In 1994 he had crashed at Imola two days before the older Brazilian, and recalled: "Ayrton was the first person I saw when I woke up in the medical centre, and all through my career he had given me many kindnesses. I was back home in Cambridge that Sunday. I could never, ever think that Senna could be hurt. So when he moved a bit in the cockpit I thought, 'He's OK'. Then the Brazilians were calling me, saying he was dead. I couldn't believe it. It was a massive, massive shock."
When he next got back in the cockpit, testing at Silverstone, Jordan told him he had all day to get back into the swing of driving. "But I put it in my mind I had to do that in half a lap. I left the pits as pumped up as possible, because I had to do it quick." Within four laps he had gone faster than ever. Senna style.
He said he still feels Senna's presence, never more so than when upholding national honour in Brazil. "I don't sit in the car and think, 'I have to be the other Senna'. But there is pressure, though it is balanced by all the support. I really do think that Ayrton is an angel, sitting alongside God and looking after me. But sometimes when I am alone I still feel as bad. Maybe I'll see a photograph of him which reminds me or some will say something about him and the feeling will come back, because he was such a good driver and such a good person."
Next Sunday in Sao Paulo, Barrichello will be a man on a mission. "I came into Formula One winning everything I could in the past," he said, "and I don't want to spend my time now getting nowhere." He'll be racing not only for himself and Stewart, but also for Brazil. And for Senna.