Ireland skipper Johnny Sexton admitted that his side lacked ruthlessness in the final round clash against France in Paris where they faced a 35-27 defeat.
Ireland entered the game needing a bonus point victory to win the championship but tries from Antoine Dupont , Romain Ntamack and Virimi Vakatawa along with a penalty try took France's tally to 35 points.
Cian Healy, Robbie Henshaw and Jacob Stockdale kept Ireland in the hunt but they eventually fell short by eight points and had to settle for the third spot behind champions England and France.
"I felt that they took their opportunities really well - sometimes off nothing, off our mistakes even, and we weren't ruthless enough when we had the chance," he said.
"We had the chance to score - a few chances to score - from five metres out.
"We had the chance to go for the try (at the end of the first half), a brave decision to try and get another try (when Sexton kicked to the corner) and we were very close but we weren't accurate enough.
"It's going to be tough to look at over the next week or so."
Sexton was replaced in the 68th minute when Ireland were trailing 20-28 - a move which did not go well with the 35-year-old.
"I was very disappointed coming off, like everyone would be," said Sexton.
"You're losing the game and you're coming off, so what would you like me to be doing?
"It was disappointment that we didn't win the game.
"We were 28-20 down with 10, 12 minutes to go, we had a five-metre lineout and we didn't capitalise.
"They are just the moments we'll look back on and regret."