But on February 24, 2001, the two Portuguese footballers stopped at the same station.
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It was an Under-15 match for Portugal against South Africa. Costinha, a young midfielder from Vitoria, was representing his country for the first time.
So was Ronaldo - and a goal in the 2-1 victory would be a sign of things to come.
But that is where the similarities end.
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Ronaldo would go on to become Portugal's greatest-ever player and one of the best to ever play the game.
Even at 38, the former Real Madrid and Manchester United sensation captains his country and continues to break international records.
Costinha, meanwhile, quit football at the age of 25 and launched a dream career in aviation.
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Now 37, the former midfielder is a passionate flight attendant - and Jose Mourinho was among his recent passengers.
Costinah told Maisfutebol in October: "Football in the lower divisions is very physical, it started to bring me problems, I was constantly injured.
"When I saw that I was no longer going to reach a high level, that I was unable to do so, I made the conscious decision to leave. Many let themselves be dragged along too late, you even had legitimacy for that, to believe, because I had a very promising start.
"But when I realised that it wasn't going to be as good as I thought, I focused on other solutions."
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Costinha failed to break into Vitoria's first-team, making only two senior appearances, although he was part of the squad which won the Portuguese Cup in 2005.
He made 13 international appearances for Portugal's various youth teams, working his way up to the Under-20s, but quickly fell into the country's lower leagues at club level.
After stints at Rio Maior, Uniao Montemor, Juventude Evora, Operario Lagoa and a season in the fourth division of Spain, Costinha called it quits in 2011.
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He added: "I started working here for another insurance company, MAPFRE, for four years, in the field of travel assistance. In the meantime, Marco Lanca, also a former player, challenged me to something that had always piqued my interest: aviation.
"I love to travel, discover contrasting realities like Sao Tome and Principe or New York, where I was recently, and then return to our Portugal. It is a career that excites me, although I was away from the company for two years before returning permanently."
Aviation isn't Costinha's only professional passion. He is also a real estate enthusiast - and briefly switched paths during the pandemic.
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He continued: "I had occasional contracts, which used to become permanent, it was like that for ages. But for the first time, at the time of COVID-19, that did not happen, my contract ended and I left.
"It was at that time that I discovered real estate, which was a breath of fresh air. I always liked dealing with people. I did it for two years and will continue to do it from time to time, but I never stopped missing aviation. So, when they invited me back, now joining the ranks, I immediately said yes."
Despite sharing the same stage as Ronaldo, Costinha admits that he is barely recognisable these days.
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And he likes to keep it that way.
He said: "Look, just a couple of weeks ago I brought Mario Rui from Italy to Portugal, when he was called up to the national team.
"And before COVID I brought Jose Mourinho, who is even from my area. But I'm no longer recognised as I used to be in the early years and I'm reserved in that respect, I never say I was a football player."
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Reflecting on his football career, Costinha remains filled with pride over that fated day he shared with Ronaldo.
And rather than considering himself a failed footballer, the former midfielder feels like a lucky man.
He said: "I think that the most emblematic moment of his career was really the first game for the national team, in the under-15s. Even today, I get goosebumps when I hear the anthem.
"Of course, it becomes even more emblematic because Cristiano Ronaldo also made his debut that day, although we were far from knowing how far he would go.
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"At the time, he was a much more virtuous player and was already on a much higher level than the others."
He added: "Deep down, I feel privileged. I had the opportunity to play football and we have to be aware that it is not for everyone, it is not easy to make a career in football. I prefer to see the glass half full.
"Nowadays, I am privileged, lucky, because I have another dream profession."
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