Enzo Maresca insists his Chelsea players must be mentally prepared for the challenge that Heidenheim will pose in tomorrow's Europa Conference League clash.

Chelsea are one of six sides, along with Heidenheim, with a perfect record in the competition so far, though the Blues lead the way in the 36-team league table having scored 16 goals in three games. 

The Blues' superior goal difference was helped by their 8-0 thrashing of Noah in their last game, scoring six goals in the first-half, which was the largest lead by an English side at the break of a major European game since Derby County were winning 9-0 against Finn Harps in the 1976-77 UEFA Cup.

Though Chelsea have already swept aside the sides put in front of them in the competition so far, Maresca does not want complacency to undermine his side's performance against the Bundesliga club.

"I enjoy every game in this competition knowing that every club tries to make it their big game," Maresca said.

"The issue for us can be that if we are not ready mentally, and we underestimate a team, they can hurt us. So we need to be ready.

"It’s an important competition, a European competition. Since we started, we have tried to share minutes with all the players in the squad.

"In some of the [Conference League] games, we have also used some young players. So we’ll see. In this moment, it’s like this, and hopefully, we can continue in this way."

With the hectic December fixture list to begin on Sunday with Aston Villa's visit to Stamford Bridge, a number of players have not travelled with the squad.

Yet Maresca provided a positive update on Malo Gusto and Pedro Neto, both of whom were absent for their 2-1 victory over Leicester City on Saturday.

"Both have trained with us," he said. "We don’t take any risks for tomorrow’s game, but I think both should be available for Sunday’s game [against Aston Villa]."