Chelsea manager Antonio Conte has found it hard to forget his side's humiliating 3-0 defeat at Arsenal in September and urged his player to make amends when the London rivals meet at Stamford Bridge on Saturday.
The loss to Arsenal forced Conte to switch to a 3-4-3 formation which sparked Chelsea into life and the Premier League leaders won 15 of their next 17 league games to open up a nine-point gap at the top of the table.
"It seems a long time ago, it's important to remember the defeat against Arsenal. It was a bad defeat. In my mind it's present, always present. I hope in the mind of our players also," Conte told reporters on Friday.
"It will be very difficult. A lot of things have changed, but for sure we are a team, we want to have a good game."
Conte is taking nothing for granted despite several managers, including Arsenal's Arsene Wenger and Manchester City's Pep Guardiola, saying Chelsea have one hand on the league trophy.
"Guardiola saying the title is Chelsea's to lose is a normal strategy by other coaches to try to apply pressure," Conte said.
Diego Costa reportedly had a row with the backroom staff and tried to force through a lucrative move to China in January but Conte is now convinced the striker has his mind only on Chelsea.
"Every week I have a lot of speculation about Diego. The most important thing is to be focused on this championship. We're in a good position," Conte said.
"Diego is important for us, he's happy to stay with us. The summer is far. It's important to stick to the present."
(Reporting by Shravanth Vijayakumar in Bengaluru, editing by Ed Osmond)