Alun Wyn Jones admittted he feared he would never play for Wales again after his Twickenham sin bin.
And the Ospreys lock insists he is a lucky man to get another crack at Test level in Saturday's Six Nations showdown with Scotland in Cardiff.
Jones, 24, said: "It was one of the most stupid and idiotic acts I have ever done on a rugby field and I thought it would jeopardise my international career. You have to have that view when you make such a mistake because the opportunities to play Test rugby are few and far between.
"I am fortunate but I've been given this second opportunity now. I don't want to try too hard because that's when you make silly mistakes but I obviously want to put some wrongs right."
Wales assistant coach Shaun Edwards confronted the British Lions second-row star in the dressing room following the costly sin-binning and warned him never to repeat his actions.
But Kiwi coach Gatland believes the incident at HQ has been put firmly behind them. Gatland said: "It was dealt with straight away in the dressing room and is dead and buried.
"Everyone makes mistakes and I'm sure he and the other players will learn from it. Sometimes you get away with having 14 men but we didn't."
But Jones accepts the Welsh management were correct to single him out for punishment. He added: "Shaun and Warren were right with what they said. When Warren first came in he said he would be honest with the players. It is refreshing and I respect him for saying it.
"It's a cut-throat mentality we haven't had before and Gats has brought that off-field southern hemipshere cutting edge. Hopefully that will provide dividends for us."
Gatland has made just two changes for the clash at the Millennium Stadium with wing Leigh Halfpenny and line-out specialist Jonathan Thomas preferred to Tom James and Luke Charteris with fit-again prop Gethin Jenkins on the bench.
Gatland said: "Jonathan is experienced and will bring us some extra mobility while Leigh offers us an extra kicking option."
Wales: L Byrne; L Halfpenny, J Hook, J Roberts, S Williams; S Jones, G Cooper; P James, G Williams, A Jones, AW Jones, J Thomas, A Powell, R Jones (capt), M Williams
Replacements: G Jenkins, H Bennett, B Davies, S Warburton, R Rees, A Bishop, T Shanklin
The WRU has launched a campaign to create a long term legacy for Welsh club rugby by highlighting the advantages of volunteering. Rhian Edwards, a volunteer at Seven Sisters, has enjoyed many benefits of her volunteering at a grassroots rugby club including being part of the Rugby World Cup volunteer workforce after being nominated by the WRU - and the WRU is asking for more people to develop their 'Welsh rugby roots'.
Wales head coach Warren Gatland and captain Sam Warburton say their first prioirty on Sunday in the opening game of the World Cup is to win against Uruguay and not get overly concerned with points difference.
With only days to go until the biggest rugby competition in the world begins, rugby fans visiting Cardiff this autumn will be able to enjoy a special display at National Museum Cardiff as part of the celebrations surrounding the Rugby World Cup.
Geraint John has taken up the new role of WRU elite coach development manager having arrived in Wales last week. WRU TV caught up with him at the WRU rugby department's strategy day at the Millennium Stadium.