Nobody is ever impressed by Ramires the first time they see him play. Perhaps it is his nationality that creates unrealistic expectations – it is a crude national stereotype, but you expect a Brazilian to be skilful and exciting on the ball, liable to an unnecessary piece of trickery, yet potentially devastating in the final third.

Ramires unwittingly helped perpetuate the assumption. The first time he came to international attention was when replacing Robinho in Brazil's 2008 Olympic squad; it was supposed he was a natural replacement. Later, he started his Benfica career with a brilliant goalscoring spell – four in his first five games. The realisation that Ramires's qualities are actually his discipline, reliability and stamina comes as something of a disappointment. Yet the more often you see him, the more you realise his value.

He remains a difficult player to categorise, particularly within Brazilian football. The genius of the system Luis Felipe Scolari created – or stumbled upon – when winning the World Cup in 2002 was that it exclusively featured the four types of outfield player Brazil does well. There were the rugged centre-backs – Lúcio, Roque Júnior and Edmílson. Ahead of them, the legendary flying wing-backs of Roberto Carlos and Cafu, protected by the solid, physical holding midfielders of Gilberto Silva and Kleberson. Up front, Ronaldo, Ronaldinho and Rivaldo were brilliant central attackers.

Outside of those four categories, Brazil has struggled to create top-class footballers this century – there is a real dearth of wide players, in part because of the prevalence of 4-2-2-2. You do not find a great deal of top-class box-to-box midfielders, nor many genuinely talented deep-lying playmakers. Defensively solid full-backs are at a premium.

Ramires is a cross between those first two categories; a wide player and a box-to-box midfielder. He found a huge fan in Dunga, the Brazil coach between 2006 and 2010, whose lopsided shape needed a right-sided central midfielder shuttling out to the flank. No one else could play that role properly – Elano did not have the legs, and Dani Alves was not accustomed to getting the ball in more central, advanced positions. Ramires's job at Benfica was similar – on the right of a diamond, asked to provide right-sided width but also support Javi García at the base of midfield. "Angel Di María was on the left, as a winger, and there was only one holding midfielder in front of the defence," he remembers. Di María, Pablo Aimar and Javier Saviola were too busy supporting Oscar Cardozo to worry about defending.

It is unusual that a player so based around stamina is also cast in such specific, disciplined roles – he is neither a headless chicken nor a solid holder, he is a hybrid of the two. "When the team are defending I try to close down the midfield, and when we are attacking I have to open up to give more space to the more creative players and be available out wide," he explains.

At his first club Cruzeiro, Ramires was nicknamed O Queniano Azul – the blue Kenyan – because of his constant running. He was regarded as a particularly brave player, and frequently told he would suit the English game. Again, a Brazilian naturally suited to Premier League football, rather than La Liga or Serie A, is something of an anomaly.

However, Ramires found the Premier League difficult at first – he was typically full of running, but too easily pushed off the ball. He was asked to play a less vertical game than he had with Brazil or Benfica, partly because Chelsea had Frank Lampard making his classic driving runs from midfield. Now, although he now finds himself playing out on the flank, Ramires appears to be a key player at Chelsea. With Lampard playing deeper alongside Mikel John Obi, Ramires can cut infield and drive at the opposition defence, with and without the ball. Furthermore, the switch from 4-3-3 to 4-2-3-1 under Roberto Di Matteo means a different job for the wide players. Chelsea are now defending with two banks of four, so require more disciplined players on the flanks – hence Salomon Kalou and Ramires are favoured over Juan Mata, who has been moved inside, and Daniel Sturridge, who is now a substitute.

Ramires's cool finish to make the scoreline 3-1 in the FA Cup semi-final against Tottenham Hotspur on Sunday was exactly what Di Matteo wants from him, and in many ways, the match at Wembley was a classic Ramires game. Browse Simon Burnton's minute-by-minute report, and Ramires's name does not feature until the description of his 77th-minute goal. He does not do anything spectacular or noticeable, yet he is always available for a pass, always in the right position, and always performing his defensive duties. He helped José Bosingwa deal with Gareth Bale, yet also gave Benoît Assou-Ekotto a difficult afternoon. He was a presence in the centre, where Scott Parker's physical exhaustion was particularly obvious when juxtaposed with the Brazilian's boundless energy.

That is further summed up statistically. Ramires is Chelsea's most frequent tackler and also their most frequent dribbler – a unique role for a Premier League player. He helps defensively and offensively, and frequently covers more distance than any of his team-mates. In the home win over his former club Benfica, which set up the Champions League semi-final meeting with Barcelona this week, he ran 11,839 metres, the equivalent of 105 lengths of the Stamford Bridge pitch. He is technically skilled too, but his mobility is Ramires's main quality.

In an age of gifted passing midfielders, the concept of raw energy can be overlooked, when frequently it is crucial in enabling the more technically proficient footballers to play. Jordan Henderson, for example, has been criticised for his contribution at Liverpool this season, but when fielded alongside Lucas Leiva, who stays very deep, and Charlie Adam, who lacks mobility, he performed an important function simply by covering a lot of ground. That was particularly obvious in Liverpool's 2-1 win at Stamford Bridge in November, when Liverpool were being completely overrun in the second half – Henderson came on with fresh legs, motored up and down, and gradually helped Liverpool push up the pitch and compete in midfield.

Henderson and Ramires would be unlikely heroes in next month's FA Cup final, but players in that mould often prosper in finals. Ray Parlour, for example, was hardly Arsenal's most talented player, yet was man of the match in the 1998 final, and scored the opener in the 2002 final. On hot days in May, he stood out simply by being able to run the furthest. Coincidentally, in that 1998 game Parlour defeated a Newcastle United side coached by Kenny Dalglish, and in 2002 the losing Chelsea team were led out by the injured Di Matteo. Those two will contest this year's final.

In an FA Cup final between two sides who have underperformed in the league, have struggled to get their expensive No9 firing, and still lack long-term direction, it may be sheer stamina that wins the day.

Drogba beats Torres in a jam

Having spent so much of the past year trying to delicately thread the ball into the channels for Fernando Torres – only to find that he is still lacking confidence even when he receives the ball in his preferred position – Didier Drogba's goal against Spurs illustrated how much easier it is with him up front. His sensational strike was reminiscent of his goal against Bayer Leverkusen in the Champions League late last year – collecting a high ball up against two defenders with no support, yet still managing to turn and score. As much as Torres would love to start the final against his old club, Drogba will surely be favoured – his record at Wembley is extraordinary, and he will be going for his fourth FA Cup final goal.

Suárez is great channel changer

Everton's left-back zone is often their most promising position going forward, yet also a real weakness when defending. Leighton Baines is a key part of their approach with the ball – he has created 35 more chances this season than any other Everton player. But his movement upfield can leave Everton prone to balls in behind, and that was exploited particularly well by Luis Suárez, who gave the centre-back Sylvain Distin an extremely uncomfortable afternoon by getting into one-versus-one situations down that side. Suárez's preferred role is still uncertain, but no forward in the Premier League is more dangerous when moving out to the channels.