Saints got the late breakthrough when Steven MacLean nodded home in the 77th minute as they moved on to 50 points, one behind third-placed Caley and one ahead of Ross County with three games left.
"It was a great result," Lomas said. "It keeps us in there fighting. It is always difficult against 10 men but even more so on that pitch.
"To be fair the ball spends more time bouncing up at your knees than it does on the ground. It is almost impossible on that pitch to play with any sort of quality but the lads kept plugging away and on chances probably merited the win."
The hosts were helped when David Raven was shown a red card after only 12 minutes for a last-man challenge on Rowan Vine which left Inverness boss Terry Butcher fuming.
Lomas had sympathy for his counterpart and said: "You can look at it two or three ways, he did put a hand on him but it was a little bit unfortunate, maybe the centre-half can get back but it is one of those things."