Frank Lampard acknowledged Chelsea must be more consistent if they are to secure a top-four finish in the Premier League following a home defeat to Southampton.
The Blues lost for the third time in four Premier League games at Stamford Bridge, Michael Obafemi and Nathan Redmond scoring in either half for Saints on Boxing Day.
Lampard's side beat Jose Mourinho's Tottenham on Sunday but, as was the case with their previous three victories in the Premier League and Champions League, they lost their next game.
Chelsea remain fourth in the table yet Lampard admitted they will struggle to maintain that place if their sequence of up-and-down results continues.
"It's a clear statement that you need a form of consistency to come in the top four because it's the Premier League - everyone is striving for it," Lampard said at a news conference.
"We are in it at Christmas; people would probably have doubted that, so I think from that perspective we can be relatively happy.
"But if we want to stay there we have to move onwards and upwards, rather than look backwards, we clearly need to win more than we have won recently at home."
Lampard and his players earned plaudits for the manner of their victory over Spurs and his former manager Mourinho.
However, the Chelsea boss conceded it is after defeats when he will learn even more about his players.
"After Tottenham we were the greatest thing in the world, they were the greatest players and I was a great manager, and today it’s questioned," Lampard added.
"That’s when you see the strength of character of someone."
Southampton started the day just outside of the bottom three, but boss Ralph Hasenhuttl was encouraged by West Ham and Bournemouth's recent wins at Stamford Bridge.
"When you see that two teams win here then why shouldn’t you also," said Hasenhuttl.
"This is more of losing the fear, don’t be afraid. Come here, be brave. I spoke before about how we want to win here."