Hart thought that Rangers' first half perfomance in Monday's game at Portman Road warranted better than a 3-0 defeat.
"I thought our first half performance warranted a better return than we got," the Rangers boss said after the match.
"We were unfortunate with their first goal, when it took a deflection and looped past the keeper.
"After that I thought we should have had a penalty and then should have scored after a great cross fell to Taarabt. Goals change games.
"We felt if we could reproduce our performance of the first half we'd be all right but we lost our legs a bit.
"Their second goal came after a slip on the touchline and it's hard to swallow because we're not getting done by great goals. We're the architects of our own downfall.
"We should have been ahead at half-time and felt that if we could replicate our performance of the first half we could get at least a draw."