For the first time, Sir Alex Ferguson detected Manchester United were trying to protect their impressive run of clean sheets last Saturday.
Edwin van der Sar has not conceded a goal in a record 12 Barclays Premier League games since Samir Nasri fired past him during Arsenal's 2-1 win over United at the Emirates Stadium on 8 November.
Yet former Red Devils striker David Sadler has voiced the theory that the record is hampering his old club's normally free-flowing style and the sooner it is broken, the more likely Ferguson's team is to end a glut of 1-0 wins.
It is not a theory Ferguson entirely agrees with.
However, he does agree an element of caution crept into last Saturday's win over Everton.
"The record is having a galvanising effect but I also thought last week we just started to protect it a little bit," he said.
"Our first-half performance was excellent against Everton. We played some really good football and created a lot of opportunities.
"But towards the middle of the game I sensed we were starting to drop off a little bit. I think that was to do with keeping the record."
But, unlike Sadler, Ferguson cannot see a problem in such an attitude, believing that if anything it will just make United harder to beat as the season enters its most crucial phase.
"It is a natural thing, particularly for Edwin who knows he is going for an exceptional record," said the United chief.
"The defenders are in that position as well, so caution is bound to come into it. I am not concerned."
The run is even more remarkable given the amount of defensive changes Ferguson has been forced to make.
Van der Sar and Nemanja Vidic are the only ever-presents in a rearguard that has been robbed of Rio Ferdinand and Patrice Evra for extended periods.
Evra is still not fully fit after a foot injury and can only expect a place on the bench at best against West Ham on Sunday, while Gary Neville has been struck down by a virus so Wes Brown will make his first start since October.