The Hammers go to Stamford Bridge on Saturday hoping to inflict a second cup loss on the Blues in four days following their 5-1 defeat by Tottenham in the Worthington Cup semi-final on Wednesday night.
And Glenn says the key to success will be forgetting the venue, and getting on with the kind of football he knows his players are capable of.
"It is crazy that away from home we have been so fragile when we have the best defensive record at home with only seven goals against us," he says.
"We have got a mental block there that needs to be unblocked and we have got to do a lot better on our travels in the rest of the season because we have got some difficult games coming up."
Glenn is certain it is a case of mind over matter, insisting: "It can't be anything else. Why have we been so solid at home, conceding just seven goals, and yet it is over 30 away with basically the same players?
"We have only collected two clean sheets away in the league this year, including Old Trafford, which must be the hardest away ground to do that, and it is the same back four and midfield.
"We conceded five goals and it can only be a mental thing. We have got to become much more difficult to beat away and we have to be able to handle it and bounce back if we concede the first goal, so we can get something out of the game.
"We did that at Leicester, but that was probably the only game in which we have done it. We are very conscious of it and hopefully we can talk our way through it.
"We need to work hard on the training ground and show improvement on our travels, keeping very safe and secure at the back."
Glenn has gone through a recording of the Chelsea defeat and he says: "I have looked at the video a couple of times and the players have seen it once. They all showered and came into the video room on Monday and sat through the whole game from start to finish.
"We stopped it several times to go through where some errors were made and poor decisions that led to our own downfall. As well as Chelsea played - and you have to give them credit because they certainly capitalised well on our errors - we felt we shot ourselves in the foot.
"All five goals were poorly conceded but the first was disappointing because what was looking like a decent first half performance with us going down the tunnel as the away side at 0-0 at half time, ended up a very disappointing half time talk simply because of that goal.
"Goals change games and it was a dreadful one to concede in the manner that we did. Hasselbaink and Gudjohnsen were completely unmarked and that is quite unacceptable, especially as we have detailed players to mark at set plays.
"Considering we are not physically a big team, generally at corners we are okay. We have only conceded one this season prior to that, when we lost to Fulham and Legwinski scored.
"Against Macclesfield in the FA Cup we conceded a few corners but defended them really well."
Glenn feels that if West Ham had gone in level at half time the outcome of the game could have been very different and adds: "The first goal in professional football is the crucial one. It is a statistic and an actual fact that if you score first, 80% of the time you don't end up losing the game, but it was a terrible goal to concede 30 seconds before half time.
"However, it doesn't excuse the four goals conceded in the second half. Sloppy passing led to those and made it a really bad day for the whole club.
"Having said that, it is only our second defeat in 10 matches, but it is the manner in which it happened that is so disappointing.
"The goals were just down to individuals not doing what they were told literally 15 or 20 minutes before they went out onto the field. They come in from the warm up and we sit them down to talk about who should be marking who.
"Normally you can absolutely nail down, guarantee, that four or five opposing players will come into the penalty box for corners and it is very frustrating when players lose concentration and forget, as players detailed to do a job did.
"Obviously there are always one or two you can't account for simply because there are players coming back from injury or who have not been playing, but instructions were given.
"That is what happened with Gudjohnsen having so much room, likewise Hasselbaink, who had far too much time to pick his spot and fire the ball home. It was a catalogue of small errors that led to a big one that cost us the game.
"Ranieri says psychologically it gives them a big advantage for this coming Saturday - we'll wait and see."
Glenn stresses that he is not criticising individuals, and adds: "We all get beat, we all draw or we all win together."
As for the transfer situation, Glenn says: "There is nothing immediate but that doesn't mean to say we have given up. In more ways than one we have intensified the search for loan players because that is what it is going to be from now to the end of the season.
"We are looking at one, two, or three loans. I could have taken several loan players in the last six months but they wouldn't have brought anything to the party, so what is the point?
"But finding the ones that can do it is easier to say than do - but that doesn't mean we don't work hard and carry on."
And possible outgoings?
"Nothing that hasn't been speculated on already," says Glenn, "we will just have to see how things develop."