Jose Mourinho has warned his Chelsea stars he won't tolerate any repeat of their flop against Newcastle when they host West Bromwich Albion on Saturday.
Mourinho's men go into the Premier League clash on the back of a 3-0 Champions League win against Schalke on Wednesday, but Mourinho is still smarting after their lacklustre 2-0 defeat at Newcastle last weekend.
The Blues boss was left fuming at his side's performance at St James' Park and revealed it caused him to get angry with the squad for the first time since his return to the club.
With second placed Chelsea hoping to cut the five-point gap to leaders Arsenal, Mourinho has made it clear he doesn't want to have to lose his cool again.
Asked if it was the first time the players had seen a different side of his character, Mourinho replied: "Yes. Because the defeat against Everton was a consequence of what football can be, you never know when you are going to lose or win.
"The defeat against Basel was a very strange one but in the game against Newcastle my feeling was not good from the first minute.
"For the new ones, with the ones I work with for the first time, maybe it was the first time they felt me but I don't want to be scary.
"I just want to influence their mentality. Make them stronger and tougher and more professional and with more ambition and not to hide behind a couple of good results."
On Sunday, leaders Arsenal will look to deal a potentially crushing blow to Manchester United's title defence when they visit Old Trafford.
Arsenal's momentum appeared to be dwindling after they lost consecutive home games to Borussia Dortmund and Chelsea, but they roared back to defeat Liverpool 2-0 in the league last weekend before becoming the first English team to win away to Dortmund in the Champions League on Wednesday.
Having won eight and drawn one of their nine league games since losing to Aston Villa on the season's opening day, they travel to Manchester knowing that victory would leave them 11 points clear of the champions after 11 matches of the campaign.
United striker Wayne Rooney poured scorn on Arsenal's championship credentials this week, saying that their recent title challenges had "faded away", but the London club's midfielder Aaron Ramsey says his side have nothing to fear from the 20-time champions.
"Absolutely not. They have had a bit of a rough start, but they have overcome that now I think," said the Welshman, who took his tally for the season to 11 goals with a headed winner at Dortmund's Westfalenstadion.
"They have had a few good results in the league and will be getting their confidence back up, but we are really confident ourselves. Our away record has been really good, so hopefully we can continue building on that."
United saw a run of four consecutive wins come to an end in a 0-0 draw away to Real Sociedad on Tuesday, but they are seeking to prolong a sequence of eight matches without defeat in all competitions.
David Moyes' side are also determined to improve on a dismal record in matches against their fellow title contenders this season, having taken just one point from previous encounters with Chelsea, Liverpool and Manchester City.
"I don't think we've shown ourselves this season on a consistent basis, not just in the big games," admitted United centre-back Rio Ferdinand, whose side begin the weekend in eighth place.
Liverpool will also hope to eat away at Arsenal's five-point lead when the Merseyside club welcome Fulham to Anfield.
Fresh from reaching the Champions League knockout phase for the first time after a 5-2 win over CSKA Moscow, Manchester City visit Sunderland on Sunday.
Manuel Pellegrini's men climbed to fifth place in the league table after demolishing Norwich City 7-0 last weekend and French midfielder Samir Nasri believes that the 2012 champions are finally clicking into gear.
Saturday (1500GMT unless otherwise stated):
Aston Villa v Cardiff City, Chelsea v West Bromwich Albion, Crystal Palace v Everton, Liverpool v Fulham, Norwich City v West Ham United (1730GMT), Southampton v Hull City
Sunday (1610GMT unless otherwise stated):
Tottenham Hotspur v Newcastle United (1200), Sunderland v Manchester City (1405), Manchester United v Arsenal, Swansea City v Stoke City