Glenn was quick to praise referee Phil Dowd's general performance but insisted 'he got it wrong' when he punished Anthony Gardner for what appeared minimal contact at best with Alen Boksic in the 69th minute.
Franck Queudrue curled the free-kick home from the edge of the box to cancel out Steffen Iversen's first half opener.
The boss reflected: "I felt the referee had a very good game, but on that one, I think he got that wrong and I think he probably got a penalty wrong for them.
"It was disappointing because I felt we deserved to win the game with the chances we created and the way we played.
"How they got the free-kick for the goal warranted the frustration because Anthony played really well, as did Chris Perry. The whole back four played well.
"It was Boksic's frustration and the referee unfortunately bought it, as we call it in the game, but that happens, and we felt that Steffen Iversen was pulled off the end of the wall as well.
"But we had the chances before that at 1-0 to really have tied the game up to be honest and that's where perhaps we've got to improve and it's something that's happened this season before.
"But we're very pleased with the way we played and that's two decent performances back-to-back away from home."
A satisfied Glenn Hoddle was left to rue the award of the controversial free-kick that led to Middlesbrough's equaliser in Saturday's 1-1 draw at the Riverside.