But when his Games experience finally became a reality on Monday it lasted only 67 seconds.
Representing the Refugee Olympic Team, the Venezuelan-born middleweight Sella was facing Dominican Republic’s Euri Cedeno in his opening bout and soon found himself lying on the floor after a few seconds.
He got up in time to survive the referee’s count but a minute had just passed when another powerful jab from Cedeno caught his face.
This left him frozen for a second.
The referee would allow no more as he felt the 24-year-old was clearly out of his depth and awarded the fight to Cedeno.
Sella did not want to leave the ring so early after all his efforts to get there.
At the age of 18, he made the Venezuelan national boxing team, but a lack of resources in the aftermath of the economic crisis in the country forced him to quit.
Aspiring for better opportunities and more stability, Sella fled Venezuela in 2018.
He sought asylum in Trinidad and Tobago, where he had been invited to compete in a boxing tournament.
The next year he was joined by his father, who is also his coach, in the Caribbean nation.
Sella worked odd jobs to earn his living but the love for boxing and the Olympic dream were always at the back of his mind.
“There was not a day when I didn’t think of going to the Olympics when I didn’t think about boxing,” he had told Olympics.com after being granted the chance to compete in Tokyo as part of the refugee team.
“When I was mixing concrete, I was thinking how that would help me in my boxing career. When I was cutting grass, I was thinking about how that will help me in my boxing career.
“When I was painting a house, or whatever I was doing, I always had in my mind what I wanted to do.”
There was, however, a nervous wait before he could make the trip to Japan.
He needed an exemption from the government in Trinidad and Tobago to travel because of his refugee status.
His appearance at the Olympic stage, though brief, left him wanting more.
“How do I feel to be an Olympian? I don’t know yet,” he said, trying to fight back tears of emotion.
“But you will see me in the next Olympics and I will answer that question better. Right now I can’t answer it.”