For Victor Wanyama, it was a statement of respect and ambition. When the Kenya midfielder joined Celtic in 2011, he asked to be given the No67 shirt. It was a move that acknowledged the club’s European Cup-winning team of 1967, the fabled Lisbon Lions and, also, one that advertised his dream to emulate them.

By any reckoning, it was a bold decision from an unheralded player who had arrived from Germinal Beerschot in Belgium for £900,000. Wanyama was 20 at the time. Was he setting himself up for a fall? “I am somebody who is not afraid to try because I believe that failing is just when you are not willing to fight,” he says. “I was ready to fight. That’s why I was not scared to take the shirt.”

Tottenham Hotspur’s £11m summer signing from Southampton speaks in soft tones as he outlines his hopes for the future which, once again, involve the Champions League. But there is a conviction to his words, and it only reinforces the physical aura of a man Mauricio Pochettino described last week as “an animal” and “a beast”.

Wanyama thrived at Celtic and one of his best performances came in the 2-1 Champions League group stage win at home to Barcelona in November 2012. He headed the opening goal and he remembers Rod Stewart, the singer and lifelong Celtic fan, blubbing uncontrollably in the stands. Wanyama won the league title in each of his two seasons at Celtic and after three positive years at Southampton – the first under Pochettino – he intends to kick on.

The connection to Pochettino was one of the attractions of the move to Spurs and it says much for Wanyama’s work ethic that he was prepared to sign up for another dose of the Argentinian’s punishing pre-season training regimes.

“It’s tough when you go through it but, afterwards, you can feel how important it is because when you go into games, you are so much fitter and you do more,” Wanyama says. “You can see that it pays off. I know the manager from before; he signed me at Southampton [for £12.5m]. He always focuses on the small details and that’s what improves players.”

Wanyama talks a good deal about improvement, in a personal and collective sense, and his primary target for the season is to improve upon what Tottenham achieved last time out, which will not be straightforward but, according to him, is possible. He has started brightly and it was his goal that secured the 1-0 home win over Crystal Palace last Saturday. Then, there is the Champions League. Thursday’s group-phase draw has made it feel real and there was excitement and optimism when the club pulled CSKA Moscow, Bayer Leverkusen and Monaco.

Victor Wanyama rises above Jordi Alba of Barcelona to score for Celtic in the Champions League in November 2012. Photograph: Jeff J Mitchell/Getty Images

Wanyama is ready to fight. He always has been, since his formative days in Muthurwa, a neighbourhood in the Kenyan capital, Nairobi, which is the sort of place, Wanyama says, that stays with people. It was rough and, as a child, he saw terrible things.

“You would be walking along or playing football and you would see thieves snatching things or someone taking a knife out to stab the other one because something had happened – he took his money, maybe. For a young kid, seeing what I saw was a bit of a torture, I would even say.”

Football was his salvation; his pathway to a “better life”. Wanyama dedicated himself to the game. At the age of 11, he played for a local team called Country Bus and, together with his team-mates, he would walk for miles in his bare feet to get to away fixtures. He cites the club’s coach – a man known as Amigo, who has since died – as an inspiration.

“Sometimes, we would walk really far, like, say, the distance between Tottenham’s training ground in Enfield and White Hart Lane [seven miles],” Wanyama says. “And then we’d have to walk back. It was a hell of a journey but, sometimes, it was fun, because you were in a big group and we were young. We would play against teams who might bring older boys but we were not scared.

“I was distracted by football, it was important for me because it passed my time and made sure that I did not get involved in other things. Amigo was really committed to helping the youth and he loved to train us, although we were playing with balls that were hand-made out of paper and elastic bands.”

Wanyama played barefoot and when he won his first pair of boots at an under-12 tournament, he found them so uncomfortable that he had to take them off. “The pitches were not great and you’d hit your toe and there would be blood everywhere,” he adds. “But you just continued. They were the surfaces we had at the time and it was fun.”

Victor Wanyama celebrates after scoring the only goal of the game against Crystal Palace last weekend. Photograph: Eddie Keogh/Reuters

Wanyama’s parents worked for Kenya Railways and he describes his family as “neither rich nor poor”. He adds: “Where we lived was OK. My parents provided what they could but they could not buy football shoes for me. There was not any day where they wanted to see me go to sleep without eating. So I was getting food.”

Wanyama is not the only famous footballer in his family. His father, Noah, played for the AFC Leopards and won caps for Kenya while his older brother is McDonald Mariga, who has played for Parma and Internazionale, among others, and is now at Latina in Serie B.

“McDonald’s full name is McDonald Mariga Wanyama and I’m Victor Mugubi Wanyama,” Wanyama says. “In Kenya, the family name comes last and I like to use my family name on my jersey. McDonald has always had Mariga on his shirt. It’s just a choice.”

Mariga has a Champions League winners’ medal from his time at Inter – he was an unused substitute for José Mourinho’s team in the 2010 final against Bayern Munich although he featured off the bench in the earlier knockout rounds, including the semi-final, second leg at Barcelona.

He was the family’s trailblazer in Europe and when he was at Helsingborg in 2006-07, he persuaded the Swedish club to admit his brother to their academy. Wanyama was 14 when he arrived and having coped with the culture shock, he enjoyed an invaluable experience.

“It was really strange, at first, because I didn’t understand any Swedish but I enjoy languages and after three or four months, I was getting there with it,” Wanyama says. “How is my Swedish now? Really bad. My Flemish is better, because I was at Germinal Beerschot for three years.

“Helsingborg really helped me. If I had stayed in Kenya, I wouldn’t have got that experience of knowing how to be a pro. They didn’t have the facilities in Kenya that I had in Sweden. I was really lucky to go there. I stayed with my brother and when he left for Parma in 2007, I went back to Kenya. I joined one of the academies called JMJ and after that I went to Belgium.”

Wanyama’s interest in British football took hold at an early age. He would go to the cinema in Muthurwa to watch the big derbies, Glasgow, Manchester and north London, and his favourite players were Roy Keane, Paul Scholes and Robbie Keane.

Spurs will be playing their Champions League home matches at Wembley this season, and the club is committed to engaging with the local community in Brent. The Tottenham Hotspur Foundation is set to deliver sports sessions for youngsters, roll out its Community Health Check programme and provide employment opportunities to local people. Speaking at one of the sports sessions at Bridge Park Community Centre in Brent, Wanyama, said: “It’s important to us that we make local people around Wembley feel involved with the club when we are playing our home matches here.”

“I was a fan of Celtic,” Wanyama says. “My brother had one of their jerseys and when he outgrew it, I took it. Even when I was very young, before I knew about the Scottish league and Celtic, I would see a lot people wearing the green and white, and going to the pub in Kenya. Celtic have fans everywhere and they have a massive fan base in Kenya.

“When I signed for the club, I already knew about their history but I did a lot of research. The story of how they beat Inter to win the European Cup in Lisbon appealed to me and I decided to get the No67. I’d also seen my brother getting into the Champions League and I had that dream to play in it. I dreamed of winning it. I was dreaming a lot.”

Wanyama has seen many of his dreams come true. He made his international debut at 15 and having become the only Kenyan to play in the Premier League, he is a hero in his homeland.

Wanyama’s dreams are now with Tottenham. He pushed for the transfer to happen in the summer of 2015, only for Southampton to block it. There was frustration, a measure of ugliness. “It’s always tough when somebody wants you and the other club makes it difficult,” Wanyama says. But he refocused and he has what he wanted. Liverpool are the visitors to White Hart Lane on Saturday lunchtime. Wanyama means business.