Edwin van der Sar approached Sir Alex Ferguson this week to say he was thinking of scrapping plans to retire at the end of the season. In his programme notes for Sunday's match against Blackpool, the Manchester United manager writes that Van der Sar, who announced in January that this would be his last season in football, almost changed his mind.

Van der Sar, 40, has been in outstanding form, and last month was named in the PFA Team of the Year for the third time in his United career. That, and United's 19th title, made him considered continuing in 2011-12, but he will sign off against Barcelona at Wembley on Saturday – 16 years after he played his first Champions League final, for Ajax against Milan.

"Edwin decided he wants to go out at the top, though he did have a wobble last week," Ferguson wrote. "He came to see me and told me he was thinking about changing his mind.

"I had to tell him to be quick about it because we are in the middle of concluding a deal for a new keeper. He came back a couple of days later to say he would be sticking with his original decision to go, which I think at his age is the right thing for him to do."

In his own unobtrusive way, Van der Sar has been one of Ferguson's best signings. United's attempts to replace their last great goalkeeper, Peter Schmeichel, were often disastrous: they used 10 keepers between 1999 and 2005, when the signing of Van der Sar solved the problem at a stroke.

In his six years at United, he has won four Premier League titles, the Champions League, the Club World Cup and the League Cup.