Nemanja Vidic believes Manchester United's creaking defence are set for a stern test of their credentials in Wednesday night's Champions League semi-final against Arsenal.
After spending a large chunk of this season revelling in lavish plaudits from all quarters, Vidic and his team-mates have come under-fire as the seemingly invincible European champions have stumbled from their lofty perch in alarming fashion over recent weeks.
The defensive trio of Vidic, Rio Ferdinand and keeper Edwin van der Sar have gone from being the rock for the most dominant side in the game to a branch of the team many have suggested is vulnerable to breakage.
Now the moment has come to re-establish their 'untouchable' aura and Vidic accepts there can be no room for any more slip-ups as the gifted attacking stars at Arsenal's disposal are more than capable of snatching an away goal at Old Trafford.
"We cannot afford even one mistake against Arsenal and expect to get away with it," warns Vidic, whose glaring error and red card against Liverpool last month allowed their chief Premier League rivals to claim a 4-1 Old Trafford win that started United's mini-slump.
"You have to be impressed with the clever, stylish way Arsenal go forward and, motivation-wise, they will be up for it because this is their last chance for a trophy this season. They have lots of pace and ideas in the attacking-third and are capable of making chances out of next to nothing.
"I'll have to be on my guard and so will Rio, but this is a team effort and that's why we have been so successful in the last few years. Defending is not just about the players at the back in this team, it starts from the front and works its way through. Look at the effort Wayne Rooney and Carlos Tevez put in.
"We're more convinced than ever that we can defend our Champions League title, but there are no favourites in this semi-final. Arsenal have beaten us in the Premier League, but we have had a better season overall.
"You could make an argument for either team to go through to the final in Rome and it will be a case of who is the best prepared, who wants the victory more. It will be a very tight tie, one decided on small details."
Going into the month of March, United's first choice defensive wall was hailed as the most solid unit in European football and more questions were being asked about United forwards Cristiano Ronaldo and Dimitar Berbatov.
However, the perceived indifferent form of the high-profile attacking stars has been forgotten amid the sudden and unexpected loss of confidence afflicting Vidic and his pals at the back.
As Tottenham showed in the Premier League at Old Trafford for 45 minutes last Saturday, speedy and diminutive midfielders can trouble United's defensive line. Indeed, Arsenal midfielders Cesc Fabregas and Theo Walcott will not have over-looked the damage Luka Modric and Aaron Lennon inflicted on United at the weekend.
However, Arsenal will also have noted the awe-inspiring response to Tottenham's audacious start, as United stormed back to record an emphatic 5-2 victory and Vidic accepts his job is to put out the fires at the back and allow his gifted attacking team-mates to do their worst.
"We've had our difficult times recently, especially the defeat in the Premier League to Liverpool, which hurt quite a bit," concedes Vidic. "I made mistakes and have to learn from them, but the good thing about being at Manchester United is you cannot stay down for long. The mentality of the club is to bounce back and the quality of players we have here means you cannot be down for long.
"I come up against the attacking players we have at the club every day in training, so no-one needs to tell me how good Berbatov, Ronaldo, Carlos Tevez or Wayne Rooney can be. They can win any game for us with one moment of brilliance, so a clean sheet is normally enough for a victory.
"We showed this quality against FC Porto in the quarter-finals. They thought the tie was won when they drew at Old Trafford, but we were angry we had been a little sloppy in the first-leg and were determined to put it right. We were totally professional in Portugal and got the qualification we needed."
United's apparently unquenchable thirst for trophies is one of their strongest qualities and Vidic believes the motivation rippling through a squad that has already won every prize the English game has to offer stems from the top.
"We are in daily contact with players and coaches who've got where they are through drive and determination, but Alex Ferguson has to be the most driven person I've ever come across," he concludes. "Our manager is never satisfied and wants to win more and more.
"His mentality has become the motto of the club. Last season's titles have to be filed away. The objective is to maintain the standards we've set and hopefully to better them. Sitting back and thinking you've already made it is not allowed and all of us want to be in Rome for another Champions League Final at the end of this season."
One of United's most bruising competitors is talking a good fight ahead of a game where his power in the air must be a concern to an Arsenal side never comfortable dealing with set-plays and Vidic would dearly love to answer his critics by scoring the goal that sends United back to the promised land of another European Final.