he often played as a centre-forward throughout his professional career, and has been described as "the definition of 'target man'" by Martin Li of Bleacher Report. Richard Beech of the Daily Mirror says that his "powerful and intrusive approach made him the lone striker José Mourinho grew to admire, and made it nearly impossible for opposing teams to isolate him and freeze him out of the game." Carl Anka of the BBC writes, "Drogba's robust playing style was so effective that he spearheaded the movement of the Premier League from the 4–4–2 era to a time where the 4–3–2–1 formation was king." Drogba is renowned for performing in big games, with a goalscoring record at club level of 10 goals in 10 finals winning 10 trophies. Carl Anka writes, "Local derbies, top four six-pointers, title challenges or cup finals — if the game was big, Drogba got bigger". Drogba was also capable of providing assists to his teammates. Between the 2009–10 and 2011–12 seasons, he managed 24 assists in the Premier League, with an average pass success rate of 61.4 percent, owing to his vision and creativity on the ball. He provided 71 assists to teammates over the course of his entire career at Chelsea until May 2012, showing that he is also a team player. Drogba was also known for his free kick ability where he would strike the ball with power and pace. Dr. Ken Bray of the University of Bath has described him as a specialist especially from central positions, and says that he "really just passes the ball very hard". He adds, "He hits it [the ball] very straight and appears to hit the ball with a very powerful side-foot action, almost like the technique used in a side-foot pass. Drogba's style is about beating the goalkeeper with speed and depth." Bleacher Report states he adopted the "knuckle ball" technique developed by Juninho Pernambucano where the ball has almost no spinning motion during flight. Drogba's trademark goal celebration saw him slide on his knees accompanied with an arm pump and a salute to fans – his celebration appears in EA Sports' FIFA video game. One of the greatest African players ever, Drogba is usually ranked among the three greatest African strikers, alongside George Weah and Samuel Eto'o. Drogba's diverse and robust playing style has seen him frequently cited as the toughest striker numerous defenders have had