Michael Essien claims the best part of Chelsea's season is yet to come as the Blues prepare for their crunch game against Manchester United on Sunday.Chelsea can go top of the standings at Old Trafford and give Essien the chance to end the season with a winner's medal as he did last season.If that happens it will represent a great comeback from the side who endured their worst run for 15 years in November last year but have now taken 25 points from a possible 27 recently.Essien wrote in his blog on Chelsea's official website: "It has been a sweet and sour season. To use a sandwich analogy: sweet bread at the top, sour filling and more sweet bread at the bottom."He added: "We started the season extremely well, had a sour middle part and are now ending strongly."We have hit a good run of form lately and have managed to haul ourselves back into the title race."We have to beat Manchester United at Old Trafford this weekend to ensure we are in the driving seat and I can assure you we are up for it."The team is playing well and I have no doubt we will give it everything we have to beat Man United."Source: Kickoff.com