He says that the first cracks in United's title pursuit will begin to appear if Sir Alex Ferguson's squad fall into the trap of believing that their recent form reflects any kind of impregnability.
Unbeaten in 11 League games, seven consecutive victories and with the prospect of Liverpool and Chelsea cancelling each other out at Anfield on Sunday, United are threatening to disappear over the horizon as they chase an 18th domestic championship.
But with history beckoning for Van der Sar, the 38-year-old has insisted that complacency must not set in on the back of his incredible achievement.
Van der Sar said: "Our defending has earned the recognition now, so maybe teams know now that when they go a goal behind against us, it is going to be difficult for them.
"Two or three years ago, Chelsea hardly conceded any goals and it is good to know, with the quality we have in midfield and in attack, that we are able to score one or two goals. But we don't feel invincible. The moment you start feeling invincible, you start losing."
Having surpassed Cech's record at the Hawthorns, Van der Sar left the pitch clutching the match ball as a memento of his feat, but he insists that personal glory can be nothing more than signpost on the route to collective success.
He said: "A lot of players claim the match ball when they score three times, so I thought I might as well take it home!
"I had a couple of records in Holland, 10 games without a goal, and a Champions League record of nine games, so this one is good. But the main thing is that we want be holding something in our hands at the end of the season.
"The record feels terrific, though. I was watching the minutes tick away towards the end at West Brom and, even though we were a few goals up, I still felt very nervous. When I saw the clock reach 85 minutes, to take me past the record, I started to get a good feeling."
Despite United's ominous surge up the table in recent weeks, midfielder Ryan Giggs maintains that the race for title remains too close to call.
Giggs said: "There is a long way to go and there are some good teams up there – Liverpool, Chelsea, Arsenal and Aston Villa, it's all close.
"The testing time will maybe come when it is the last stages of the Champions League, the FA Cup, important league games. That is when your squad becomes important."