Murray Davidson netted an early goal for the Perth side, but they had Steven Anderson sent-off in the first-half before Chris Millar followed him down the tunnel after the break.
Paul Dummett levelled shortly after Millar's departure and the hosts then spurned a number of chances to secure victory.
Lennon said: "It was frustrating dropping two points. We started well and I was disappointed at losing the early goal, especially as we had talked about the runs made by Murray Davidson which should have been tracked by John McGinn.
"Apart from that the young man showed great maturity and could have scored two or three goals.
"For the second week running we created so many chances, but we need to be ruthless in front of goal.
"I thought we made it count when we had one extra man and then two and was delighted with the number of crosses and chances we got in the box.
"Their keeper (Alan McMannus) has made some terrific saves, but while I'm delighted at the chances we are creating we need to take them."