The Szymanowski siblings arrived in Spain from Argentina as children – and brought their football with them. "We arrived at night and the next day we went out to play in the neighbourhood," recalled Leganes attacker Alexander Szymanowski with a smile. "We met two boys, the first Spanish kids we'd come in contact with. We played a game and they were impressed… especially with Marianela.

"Ever since we were small I remember playing football with her everywhere we went," he continued. "We've always been a team. It was always us against the neighbours, against our friends, against the guys who lived opposite us…" His sister, Marianela Szymanowski, who plays for Valencia, laughs as she confirms her brother's words when speaking to FIFA.com: "Us playing football together basically sums up our childhood. I don't remember anything else."

The Szymanowskis versus the world - first on the unpaved streets of an underprivileged neighbourhood in the outskirts of Buenos Aires, and then in the mountains of Madrid, where they arrived aged 12 and ten respectively.

They were inseparable, even if they fought every day. "We would always fight when we were younger, and we didn't hold back when we hit each other," said Marianela. "We drove our parents crazy." Now, however, they could not be more supportive of each other.

Marianela recalls being in a state of shock a few weeks ago while watching her brother play against Atletico Madrid at the Vicente Calderon stadium, the very arena where, as teenagers, they managed to get in to see Atletico play Barcelona. Back then, thoughts of one day playing professionally among the game's elite were a mere pipe dream. "We went from almost begging for a ticket to me being there watching him play," said Marianela. "I couldn't believe it, I swear. I usually shout and cheer him on when he's playing, but I was speechless. I was amazed. I was like a mannequin during the match."

Sticking together Alexander's route to the top was an arduous one. At the age of 28 he is currently in his maiden season in the top flight, having spent several years in the second and third divisions. During that time there was only one person who had absolute faith he would succeed. "I don't know what she saw in me, but she was the only one who said I'd make it," he said. "I was just happy to be making a living from football and to have a decent wage." Marianela explained further: "I didn't say that because my emotions were getting the better of me, but because I could see he had talent. He just needed to develop physically and psychologically. I used to say to him 'it might not happen until you're 27 or 28, but you're going to make it'. And that's how it turned out."

It was not until Marianela was 16 and playing in a futsal team that she began taking football seriously - much later than her brother. By the time she was 19, the striker made her top-flight debut with Atletico. "She plays so well that in the end she just had to make it her job," joked Alexander.

Nevertheless, her playing career has been far from easy. "In 2011 I got kicked and tore both meniscuses, and on top of that the whole joint was damaged," Marianela explained. "It was a very strange injury." That was the start of two and a half years of struggle that included two operations, as well as multiple examinations and visits to leading specialists that Alexander found. However, nobody was able to help her recover.

"I couldn't even have a normal life," Marianela continued. "I couldn't walk and wasn't able to stand up for more than half an hour. It was no life at all. I couldn't even make any progress academically because I couldn't concentrate on reading or studying due to the pain." Still, the most trying aspect of it all was the threat of never being able to play again.

Alexander is in no doubt why that ultimately did not happen: "Her character alone is what's helped her get back to football. Anyone else, myself included, would've given up. It's at times like that when you see the kind of sister you have. Considering what they get paid in women's football… it cost her so much time, health and money…"

For Marianela, however, quitting was never an option: "I would never have forgiven myself if I hadn't kept trying. I told myself 'I'm not going to stop until they amputate my leg. If I've got two legs and two knees I've got to keep going until I'm not in pain any longer. That day has to arrive'."

When Marianela met Dr. Ramon Cugat, one of the world's foremost specialists, it finally did. "It was like meeting an angel in the middle of a dark tunnel," she said. Once he learned of her situation, he treated her free of charge. His diagnosis, which differed to the others Marianela had received, helped her return to the football pitch in three months.

Unfinished business While her lengthy spell on the sidelines was a dark time, Marianela insists there were positives too. "Not being able to play brought me much closer to my brother and I was able to support him by watching his games," she said. Furthermore, she unearthed a new passion: "I frequently asked myself why I wasn't getting better and that led me to read a lot of things about possible treatments. I became a bit of a freak about nutrition and measures to help improve performance. This year I want to start a physiotherapy course at the INEF and I'd like to have my own clinic at some point in the future.''

Before then, she still has plenty more football left in her – and an objective to achieve. After her recovery from injury Marianela helped Argentina finish fourth at the 2014 Copa America, just missing out on qualifying for the FIFA Women's World Cup 2015™. However, she was not at 100 per cent during the tournament. "This sounds a bit dramatic but I'd used so much energy getting better that my mind hit a low point and I didn't feel like myself. So I still feel I've got a point to prove with the national team."

Regrettably, La Albiceleste women's side have not played again since then. "In my view it's down to there being a much more prevalent macho mentality in South America than in Europe, and that leads to women's football being neglected," Marianela said. Undeterred, she remains optimistic: "There are signs of positive changes. If things are improving in Spain and other countries, and in South America a little bit too, then we can hope things will keep going in that direction, even if I think we've still got a long way to go."

Her brother has likewise not given up hope of seeing her in national team colours once more. "She's the international in the family so I'm always putting that pressure on her," Alexander laughed. "Hopefully we'll be able to see her soon at a World Cup, Olympic Games or Copa America. I'd be going crazy in the stands."

Whatever happens, Alexander and Marianela will continue to support each other, just as they did as children, taking on the world with their football.