John Obi Mikel at pains to show Chelsea his worth

It was just four months ago that coach Carlo Ancelotti backed midfielder Mikel to be a major part of his revolution at Stamford Bridge.

To many observers, the Nigeria international has failed to live up to his potential since his £16million move from Lyn Oslo to the club in 2006.

Ancelotti's arrival in the summer had given him a new lease of life after a few years of stagnation in south west London. It appeared the controversy of his transfer, where he seemed to be originally heading to Manchester United rather than the Blues, would overshadow his career.

He showed muted progress under previous managers Jose Mourinho, Avram Grant, Luiz Felipe Scolari and Guus Hiddink before Ancelotti took the helm and even though he signed a new long-term contract in the summer, the jury in the stands was still out.

A niggling ankle injury has further hampered his plans to secure a regular starting spot in Ancelotti's team and speculation has mounted that the former AC Milan coach is looking elsewhere for a defensive midfielder to better fulfil his requirements.

The Italian may have hailed Mikel as the new playmaker in a blue shirt on his arrival in July, however the 22-year-old's lengthy spell on the sidelines since then has ensured a less favourable point of view.

Michael Essien is set to be on the bench tonight as he rests a slight problem with his knee and it gives Mikel (right) the opportunity to prove he can not only be a solid replacement but an inspiration.

He said: "I am happy with the way things have gone with my injury. I was meant to be out for two to three months, so it is good to be back early. My ankle is still not 100 per cent. With injuries like this you have to play with the pain. It takes between four to five months before it heals properly. It still hurts but the doctors said this is what you have to deal with and you have to play with it like that. This is what I'm doing right now.

"Sometimes it's frustrating but you just have to do it. I feel fit enough. I want to help the team keep their good form going. It is what we have to do. Our aim this season is to win every title. I want to help them do this."

The first priority is to secure top position in Group D with a victory tonight in the hope Chelsea secure an easier draw in the knockout phase.

Porto have lost just once in Europe this season - a 1-0 reverse at Stamford Bridge - and victory for Jesualdo Ferreira's side will give them the edge going into the final group clash. It is very much a pressure game for Ancelotti and his Chelsea side, who have failed to sparkle on their travels in Europe this season.

Ancelotti said: "Porto are a good team but while we respect them we have no fear. We want to put our personality and quality on the pitch. We want to arrive at first place in the group."

The encounter with Porto is just the first of four away matches which could have a large say in how well Chelsea do this season. John Terry certainly feels the next two weeks, where the club face matches against Arsenal and Manchester City in the Premier League as well as Blackburn in the Carling Cup, could make or break their season.

The captain added: "It's four away games in a row. That's the challenge major title-winning teams rise to."