Gavin Gunning headed United into the lead after just two minutes but Brian McLean put through his own net two minutes after the break to earn Lomas' side a point from a 1-1 draw.
The result means Saints have drawn five of their last eight matches to leave Lomas a little frustrated.
"If we were a bit more clinical we would have gone down the road with three points," he said.
"The performance was good but the conversion rate of chances to goals must be the poorest in the league. That's what's causing us to draw so many games.
"In saying that, their keeper (Radoslaw Cierzniak) made some terrific saves.
"He made a great stop from Liam Craig in the first half that we thought was going to be nestling in the net, and he had another one right at the end from (Gregory) Tade.
"That is what he is there for. We just need to keep working hard on our finishing in training because we are creating a lot of chances.
"That said, I'm sure the fans would have been delighted with that display. We asked for a reaction because the second half at Aberdeen wasn't great.
"We brought a great support to Tannadice again and I think the players knew they owed them a performance and they got that in abundance.
"That was for the plucky souls who braved the wind and the rain at Aberdeen last weekend."