Nemanja Matic Benfica Ramires Chelsea
Benfica midfielder Nemanja Matic and Chelsea's Ramres battle for possession in the Europa League final, 15 May, 2013. Reuters

Midfielder Nemanja Matic is targeting the English Premier League and Champions League titles, while relishing the chance of working with the "best coach in the world" after completing his switch back to Chelsea from Benfica.

Chelsea signed Matic for around £21 million on Wednesday, with the Serbian midfielder inking a five-and-a-half-year contract to assert his long-term commitment.

"I am very happy for this opportunity to be back at this club," Matic told the club's official website. "I feel very good because of that and just want to say I will give my best to help the team and make the Chelsea fans happy.

"First, I want to play and help the team to win the Premier League, and if it's possible to play in and win the Champions League in the future," Matic, who is cup-tied in Europe's premier competition added. "I want to win titles here."

The 25-year-old was used as a makeweight in the deal that brought David Luiz from Benfica in 2011, with the midfielder then going on to establish himself with the Portuguese club, and turning himself into one of the most coveted defensive midfielders in Europe - a reason why Chelsea did not hesitate to pay such a big amount despite initially selling him for next to nothing.

"I've played regularly in a big club at Benfica, where it is not easy and there is a lot of pressure. In those years I learned to be a winner and play under that pressure," Matic said. "I developed tactically in Portugal also, training very hard and I believe I am better physically also."

Matic revealed he had spoken to Jose Mourinho, and expressed his excitement at the opportunity of working with one of the best managers in the sport. "He said to be professional, to give my best for the team," the Serbian international said. "It's exciting to work with him, he is the best coach in the world and I want to work with him for a long time. I am ready."

Matic might not have been able to make a name for himself during his first spell with Chelsea, but the former Benfica man said he was keeping regular tabs on the club's progress courtesy compatriot Branislav Ivanovic.

"I always watch games when I have the time and step by step, game by game, Chelsea is growing," he said. "I speak with Branislav Ivanovic, my friend and international team-mate a lot, a few times each month, so I know everything about the club!

"Of course it is not the same now. The team is younger now. When I was here before most of the players were very experienced, 30 years or older, and now we have a strong team with a big future."

Chelsea fans were given a bird's eye view of Matic's talents in the Europa League final against Benfica last May, a game in which Ivanovic scored a dramatic late winner to give the Blues another European crown.

"It was a good game. Branislav scored in the last minute, so I was not very happy, but if somebody must score this goal, I was happy for him," Matic added. "We were unlucky to lose, but somebody had to, and it was good to be in the final.

"I said congratulations to Chelsea and wished them all the best. People said I played well but I have not seen it again after, I couldn't watch it because we lost. I gave my best, like always."