"Yes, I am Brazil's best," says a beaming Sandro before punching the air in mock ecstasy, which he tends to do every time he hears something that pleases him. But Sandro is not talking about football. He is talking about a sport he has fallen in love since moving to England in September 2010: darts.

"It started when I saw it on television and I found it interesting and enjoyed the atmosphere," he says. "A colleague of mine said: 'If you like it, I will buy you a board,' and I put that up in my house."

He became such an enthusiast that earlier this year the Premier League's production company arranged to film him interviewing Bobby George, the 66-year-old self-styled King of Darts, whose exuberant personality made him something of a soulmate for 23-year-old Sandro. "Bob gave me a bit of background on the history of darts and now he and his son come around to my house and we play most weeks. I gave my mum two dartboards to bring back to Brazil and now everyone at home is playing, too."

Sandro explains most of this through an interpreter, but when he does break into English he speaks it well, giving the impression that the interpreter is present either to safeguard against misunderstanding or as part of an elaborate prank; you can never be too sure with Sandro. "He is a lovely character, absolutely mad," says Harry Redknapp of a player who this season dyed his hair pink and blue for larks and who regularly entertains his team-mates with japes such as the martial arts routine that the left-back Danny Rose posted on YouTube.

But Sandro is serious about his football. When Fulham's midfielders arrive at White Hart Lane on Sunday afternoon intent on denying Tottenham the win that would ensure them a top-four finish, they will be going up against a man who is so driven by the desire to gain Champions League qualification that a couple of months ago, when Tottenham's challenge was faltering, he took some of his team-mates aside and gave them an impromptu, impassioned team talk. "I said: 'We have to vibrate and show passion, even if it is just winning a tackle, it doesn't always have to be a beautiful football.' That was the time to be more humble and just go and do what we had to do to make sure we got three points rather than made a pretty game. So it was more about bringing passion and heart and blood and sweat on to the pitch."

The Champions League is special for Sandro. When mention is made of Spurs' 0-0 draw with Milan in March 2011, when Sandro marshalled the midfield superbly, the memory triggers another joyous punch of the air. "That is the game that everyone talks about as the one where I showed the player I am," he says. "Football in Brazil is very different and it was hard for me to adapt to playing in England at first because it is only when you get here that you realise how fast and strong the game is. It took me about five months to realise that in my position I had to take only one or two touches. It was in the game at Milan that I realised I could make it in Europe. It was a great experience and for us, the players and the fans, we want to get back to the Champions League."

Sandro has experience of conquering a continent, having won the South American equivalent of the Champions League – the Copa Libertadores – with Internacional in 2010. He believes he can emulate that feat at Tottenham. "I am part of a club's history because I helped Internacional to win the Copa Libertadores and I want to be part of Spurs' history too by chasing the Champions League and other cups. Day by day I want to identify myself more with this club by winning things."

Tottenham's renewed push for the top four began after Scott Parker's injury led to Sandro returning to the starting lineup after recovering from injury himself. "He has been amazing in the last few weeks," Redknapp says. "He has got a great future here. We are really pleased with him and next year hopefully he will stay clear of injury and we will see the best of him again."

The best of him belongs in the Champions League. "We just have to concentrate on beating Fulham to make sure we finish at least fourth – and if Arsenal lose and we finish third, that would be perfect," he says before punching the air in delight.