Ashley Cole has warned Arsenal to expect a different Chelsea side on Monday night from the one that has won only once in seven games.
The faltering Premier League champions will be at full strength for the first time in four months for the top-of-the-table clash at the Emirates Stadium, where they romped to a 3-0 win last season.
Chelsea are on their worst run in the league for more than a decade, having won just one of their last seven games and slumping from top to fourth spot.
Injuries to John Terry, Frank Lampard and Michael Essien hit them hard but all three are back, with Lampard set to start his first game since August.
Cole, the England left-back, is confident Chelsea can reignite their title defence with a victory over his former club.
"We've been disappointing in our last six games and it's a big contrast to how we started the season, but we have a lot of big players back to fitness and it's going to give us a boost," he said.
Playing without top players would hurt any side, he said.
"The players who have come in have done a good job but you're always going to miss JT, Lamps and Essien. We seem to play better when they are all in the team.
"They're major players for us and we have missed their personalities, desire, will to win and leadership. We have been unlucky in games, even though we haven't been playing well. We have still had a lot of shots and chances.
"It has not gone our way but, now the big guys are back, hopefully we can turn our season around. We're fourth in the table; we have to get back on track."
Carlo Ancelotti, the Chelsea coach, believes Arsenal are one of several teams who could wrest the title from their grasp.
"Arsenal, Manchester City and Tottenham have an opportunity and the skill to fight for the title until the end," he said. "It will be a race with balance because a lot of teams have the ability to win, not just [Manchester] United."