Such was Carlisle's general superiority that they won a corner count 12 to two.
Kavanagh said: "We are disappointed not to have won it considering how well we played in the first half. Obviously Orient were looking a bit leggy after being taken to extra-time (by Stoke in the Carling Cup) on Wednesday evening and we should have capitalised but we didn't.
"A dubious penalty was given. We didn't see it that way but he (referee Graham Horwood) gave it and goals change games.
"We had a lot of possession yet at the end we were happy with a point because we went a goal down. We are probably more happy with the performance than the result."