Warren Gatland admitted Wales hit the self-destruct button after their RBS Six Nations title hopes bit the dust with a 26-20 defeat by France.
Wales trailed 20-0 at half-time after gifting intercept tries to France winger Alexis Palisson and fly-half Francois Trinh-Duc.
Wales threatened another dramatic comeback as they rallied to 20-13 with two penalties from Stephen Jones and a Lee Halfpenny try.
But Wales had left themselves too much to do and France sealed the victory with two late penalties before Shane Williams scored a dazzling consolation try.
Wales coach Gatland said: "We have been the architects of our own demise. Two intercept tries were really costly. It is hugely frustrating.
"We felt if we kept the ball in hand we could finish over the top of France in the second half.
"Unfortunately we pushed the self-destruct button and gave away a couple of intercept passes. At no stage did we feel under pressure because I don't think they played a lot of rugby.
"If we can stop being our own worst enemies and get it right we are not far away from being a very good side.
"We could have thrown in the towel at half-time but we played some fantastic rugby in the second half and showed some great character and put ourselves in a position to win the game. That was the most positive aspect I will take out of today's game."
Wales also conceded an intercept try against England and defence coach Shaun Edwards admitted teams had found an Achilles' heel.
"To keep France to no offensive tries was a great effort but there is no doubt people are doing their homework and have seen they can get intercepts because over 30pc of our tries conceded over the last 18 months have come from intercepts."
Wales attack coach Rob Howley revealed James Hook had apologised at half-time for throwing the sixth-minute pass that allowed Palisson to score.
"We have one of the best defence coaches in world rugby and we let him down today. It is as simple as that," said Howley. "If we hadn't thrown those two balls we would have won the game."
France coach Marc Lievremont admitted his heart was in his mouth as Wales launched their comeback.
Two weekends ago Wales hit back from 21-9 to snatch a dramatic late victory over Scotland. But Les Bleus took a giant step towards potential Grand Slam glory.
"I am very happy to have won three games but there is still a lot of work to do," said Lievremont.
"We lost a lot of coherence in the second half. It was like watching the spectre of the Wales-Scotland game appear before us. I am very happy with the win but that is mixed with relief after that second half."