He ordered a high-tempo start against the Saints and Les Ferdinand's goal vindicated that approach, but Glenn was disappointed that the lead wasn't built on while Spurs were in charge.
"I asked the team to play with a very, very high tempo for 20 minutes or half an hour," revealed Glenn. "That went perfectly to plan.
"I think we need to learn a lesson from there because we had Southampton on the rack and should have taken them from there. If we are to become a better team we've got to do that.
"We came down a peg or two and they came up a peg or two. To be honest, it wasn't a fantastic performance from us but, I'll tell you what, it was a significant sign from us.
"We played great at times, but a little bit indifferent at times and still got three points. That hasn't happened here for a long time and I think that's a great sign for the club."
Glenn says it is a great sign that the team can still reap three points from a sometimes 'indifferent' performance against Southampton.