David is looking to put the memory of Damien Duff's effort behind him when he kicks off 2003 - and Glenn is confident he can do so.
"There is no need to have a chat with him; he is an experienced goalkeeper who has let in a goal of the sort that, hopefully, he will not let in again," says Glenn.
"It is the cross you have to bear as a goalkeeper, that if you make a mistake you don't get away with it.
"A midfield player, a striker, a winger, can make a mistake and not be punished in the way that David was, with the ball ending up in the back of the net - all goalkeepers know that, and it is the position they play.
"He regained his composure very quickly and had to pull off a couple of saves in the first half which he did very well."
Many aspects of the Blackburn performance pleased Glenn, who adds:
"Overall, I thought David was very well protected, particularly by the two centre backs.
"Gary Breen deserves a special mention after not having played for a couple of months now.
"He has been training hard and waiting for an opportunity; he took it with both hands but he must maintain that level of performance.
"Christian also did well and he was supported by the midfield who put a wall up in front of the two centre backs - and we looked safe through the middle.
"Michael Carrick had a wonderful, marvellous, game - especially in the second half.
"We had a game plan to stop Tugay which very much involved Joe Cole, and I thought he did that to perfection.
"Tugay's influence in the first half or hour was, if not non-existent, limited, because he normally pulls the strings for Blackburn.
"We decided to sit Joe around Tugay and it worked very well; we spoke about it in the hotel on Saturday morning, and we showed him the video evidence of where Tugay goes to receive the ball.
"A picture paints a thousand words - and Joe played it to the letter; when Blackburn were attacking and Tugay hangs back to receive the ball Joe was coming around him and stopping that ball being played to him really well.
"When we won possession Joe was under orders to break away from Tugay, make space, and play with Ian Pearce who was playing as a lone striker - and did that very well.
"At half time we spoke about Yorke coming on and playing behind the front two and, lo and behold, we did have the game plan for how they kicked off the second half.
"Michael sat round Yorke and again nullified Yorke's contribution to the game, as well as playing his own game when we were in possession.
"I thought Steve Lomas and Trevor worked their socks off in the wide areas and in that good spell in the second half they were very influential getting down the sides of Blackburn.
"It was a thoroughly professional performance that deserved more than the point it got."
Gary Breen replaced Tomas Repka, sent off against Fulham, in the starting line up at Ewood Park, and Glenn explains:
"I just felt after what happened to him on Boxing Day it wasn't right to play him at Blackburn.
"Gary Breen has now taken his opportunity and there will be another day for Tomas but unfortunately that might be in the distant future because he is going to miss four games now.
"But he is going to have to serve his punishment like a man."
That punishment begins at the weekend, but the actual games he misses depends on West Ham's progress in the FA Cup.