The SPL champions looked set for a routine victory after Efe Ambrose's header - but the hosts stood firm and managed to snatch a leveller eight minutes from time when Nigel Hasselbaink curled home sweetly.
Lomas said afterwards: "It is an old cliche but it was game of two halves and we are not stupid, we know it could have been well and truly over by 30 minutes.
"We could have been looking at a long evening if it wasn't for our goalkeeper Alan Mannus, who made four or five great saves, and the back four.
"You have to hold your hands up and say Celtic's passing and movement was a joy to watch.
"But we had a change for the second half when we put Gregory Tade on, went to four in midfield and were then able to compete and I think we were well worth it in the second half."