Frank Lampard has challenged his Chelsea players to relish the underdog tag in their Champions League quarterfinal tie with Real Madrid and warned: "If you can't handle the pressure, you are not a big player."

The Blues travel to the Santiago Bernabeu for Wednesday's first leg with Lampard in caretaker charge after a dismal campaign in which they sit 11th in the Premier League, having fired head coach Graham Potter nine days ago -- less than seven months into the job.

- Hunter: Chelsea a pale imitation of Madrid Galacticos

Madrid are currently second in La Liga, but thrashed Liverpool at the round-of-16 stage and produced another statement victory in in last week's Copa Del Rey semifinal, beating Barcelona 4-0 at Camp Nou to advance 4-1 on aggregate.

Lampard's first game in his second spell as Blues boss ended with a 1-0 defeat at Wolverhampton Wanderers on Saturday and he issued a rallying cry to his beleaguered squad as they attempt to avoid a repeat of last season's Champions League exit at the same stage against the same opponent.

"When you get to this stage, there's always going to be pressure," Lampard said. "Are Real Madrid favourites? Yes and I understand why. That's the difficulties of our season. I don't think that is a problem.

"There is no better carrot in football than trying to prove people wrong, being the underdog and have a good result. It's one of the best things I've been part of. I think that is a nice challenge for us.

"I'm not worried about that. In terms of the pressure I am not worried about that. Football at this level is pressure. If you can't handle the pressure you are not a big club, you are not a big player or a participant in it."

Chelsea have spent around £600 million on new arrivals since new co-owners Todd Boehly and Clearlake Capital completed their takeover last May but the players have faced repeated accusations of lacking sufficient character in a turbulent campaign.

But Lampard said: "In terms of the character I think it's normal in a season where a club like us falls below the levels we want, the character gets questioned. It is probably one of the first things to get questioned at times in defeat.

"The only thing the players can do is prove it on the pitch. People can view it where they can see it. There is a lot we do behind the scenes, on the training pitch, around the dressing room, talking to the players.

"My job is to convey to them the need to train at a level, to have the mentality is at a certain level, individually and as a group. The rest, they have to show it. You can talk as much as you want, but the players have to show it on the pitch.

"I'm absolutely not questioning the fact they have a lot of character in the group because I've seen the dressing room and understand football. There is character. Nobody wants to not win football matches.

"But sometimes players can take a hit on confidence and sometimes a lack of confidence can look like a lack of character. That's my job to [correct] quickly. I've only been here a short time, to find those areas, find out which players need help or where the group needs help and try it give it the help it needs. Then it's up to them."

Chelsea could be set for a major boost after Thiago Silva was part of the 24-man squad which travelled to Madrid. The 38-year-old has not featured since Feb. 26 due to a knee injury. Cesar Azpilicueta (concussion) and Mason Mount (pubic bone) were also included.