Frank Lampard has challenged his Chelsea players to show tougher "personality" to fight for their Stamford Bridge futures.
Lampard has insisted Chelsea's run of just one win in five matches has not yet altered his view on January recruitment plans, now the club's FIFA transfer ban has been lifted.
But the Blues boss lamented a lack of steel in Saturday's 3-1 Premier League loss at Everton - and called on his players to hit back in Tuesday's crucial Champions League clash with Lille at Stamford Bridge.
Asked if the last few weeks had altered his thinking on recruitment, Lampard said: "That's always pretty fluid, so I haven't got anything exactly to say 'I need this, this, this'.
"I wouldn't say my mind is set on anything to be changed. But you do learn from your players in tough times, not just in terms of what they do on the pitch but how their personality is.
"That was the disappointing thing at Everton, it wasn't just that we were slightly off - I didn't like that there were individual contact moments across the game that we lost. Because that's a personality thing as much as anything else."
Lampard admitted Chelsea's recent sticky form hands him his first big challenge as Blues boss, and wants his players to embrace the pressure of Tuesday's must-win clash.
"It is a test for us and it was always going to come: the way we are, the nature of the Premier League, this was never going to be a plain-sailing, invincible season from our point of view; teams need this test," said Lampard.
"Big games like this, they are crucial for the players. You can be defined as an individual and a group by success.
"I was fortunate to have big nights like this as a player, and they are the ones that stick in your mind.
"So these are big opportunities now for the team, particularly the young boys when it's quite new to them, to make a mark. So I think it's good, I like the pressure of this game being knock-out.
"If we're going to do anything good here, we're going to have to have lots of these nights."