Simon Church scored the only goal of the game just after half-time although the Hatters had chances through Chris O'Grady, Dominic Blizzard and Michael Raynes late on.
Gannon said: "Credit to Orient, they had a good shape and there was good energy from them. You can see why they're doing so well at the moment.
"I adjusted things a little bit for the second half, and it worked to a certain extent, but unfortunately we just couldn't find that equalising goal.
"By and large I have been very pleased with the lads. It's been a tough period for them."
Source: Team_Talk