Cesar Azpilicueta believes Chelsea's signing of Christian Pulisic serves as a warning to the squad that the club can easily replace them if they don't perform.

Chelsea slumped to a disappointing 0-0 draw at home to Southampton last night just hours after they'd announced a £57.6m deal for Pulisic, who will stay on loan at Borussia Dortmund for the rest of the campaign.

It is the third most expensive acquisition in Chelsea's history and at 20-year-old, demonstrates how the club are already planning for the future.

Azpilicueta has welcomed the USA international's move to Stamford Bridge, but feels it also sends a message to the current group.

When asked by Standard Sport if the Pulisic deal is a reminder that the players can't afford to drop their standards as the club consider other signings in the market, he replied: "Of course. Chelsea is a top club and the competition is very high.

"Every moment we need to get results, we need to perform. That has been the case for a long time at Chelsea and will be the same now.

"Obviously I am very happy that Chelsea have signed Pulisic. He is a talented young player and will come in the summer.

"For the next six months he will be with Borussia, but I'm happy that we are getting young players. Hopefully he can be very good for us."

Azpilicueta has also urged his team-mates not to make the same mistake as last season and miss out on the top four for a second time.

Chelsea are currently in fourth spot, but picking up just one point from home games against Leicester and Southampton has allowed Manchester United to close the gap from 11 points to six, while Arsenal are just three behind.

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The Chelsea captain added: "After missing out on the Champions League last season, the minimum for us this season is to finish in the top four.

"There is still a long way until May. Sometimes during the course of the season you go through better periods and bad periods.

"At the moment, we didn't win a game at home and the feeling is not positive. But we need to learn from it.

"We can't change the result now, but we can work on improving - we still have a lot of games to play and we will have to fight hard to get our targets.

"We need to take seriously our part - we don't need to focus on other teams. It's true that in the last few games Manchester United have won, they are in a good mood, playing with confidence and getting results. But we need to focus on ourselves.

"It's true that after two good away wins at difficult places to go (Watford and Crystal Palace), we need to consolidate at home.

"The key is to be really solid at home to get our gains because we know how tough the Premier League is and we have to do better."