Goals from Les Ferdinand and Michael Carrick condemned us to a 2-0 Premiership defeat at Upton Park on Saturday.
"We've got to make sure that we don't perform like that for the remaining games, that's the bottom line," stated a disappointed Glenn.
"If we do we're not going to achieve our ambition, which is to get into Europe.
"We have to draw a line under that performance.
"There are still 27 points available and a lot of clubs clambering to get into those spots."
Glenn conceded that we didn't show the same desire as the Hammers but insisted there was no problem with attitude.
"It wasn't different going down the tunnel but sometimes you don't start a game well and that happens away sometimes," he added.
"But we've started like that in games before and turned it around, started to control the game and look like we were going to get something out of it.
"We didn't get to that stage and that was disappointing.
"West Ham deserved their victory, no doubt about that and we have to bounce back when we play Liverpool at home."
Glenn Hoddle has warned that there can be no repeats of the display at West Ham if we intend to qualify for Europe this season.