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
Wales Head Coach Rob Howley talks to WRU TV's Sebastian Barrett about the 36-man squad he has just named for the forthcoming Under Armour series, which includes two uncapped players, Ospreys duo Sam Davies and Rory Thornton.
Head coach Rowland Phillips is deligthed he can now call BT Sport Cardiff Arms Park home for his Wales Women's side, who launch their international season next month with games against Scotland and UK Armed Forces in the heart of the capital city.
Wales Sevens star Sam Cross has put his home town club of Brynmawr on the map after winning a silver medal at the Rio Olympics with Team GB. His club have now honoured him by naming their players bar after him, as WRU TV discovered at the official launch, recently.
One of the newest members of the Principality Premiership, Bargoed admit it's proving to be a steep learning curve at the highest level, but are determined to become a force to be reckoned with. WRU TV visited the club last weekend when they took on Llanelli.
Table-topping Aberavon travel to north Wales to tackle RGC 1404 as both teams defend unbeaten starts to the season in the Principality Premiership. WRU TV's Graeme Gillespie visited the Wizards to see how their preparations were going for the game of the weekend.
The Half a Game initiative is currently sweeping across Wales and proving a major success. The scheme aims to give every young player at least half a game every weekend. WRU TV recently visited a festival in Narberth where clubs have fully embraced the initiative.
Both Bargoed and Swansea were seeking their first win of the Principality Premiership season this afternoon. It proved a fruitful day for the hosts - not only did they win, but Bargoed claimed a try bonus point.
Cardiff managed to keep their unbeaten record at home intact, but only just as Bridgend made them work extremely hard before the Blue and Blacks secured a hard fought Principality Premiership win at the BT Sport Arms Park last night.
Former Wales back row Andy Powell gives a guided tour of The Wern, home of Merthyr RFC, who are determined to prove a lot of people wrong and make their mark in their first season in the Principality Premiership.