Jamie Roberts has revealed he had sleepless nights and did some "soul-searching" following a poor performance against Australia which resulted in him being dropped by Wales interim head coach Rob Howley.
The Harlequins centre was left out of the starting line-up for the victory over Argentina last weekend, paying the price for defensive lapses in a 32-8 defeat to the Wallabies.
Roberts has been restored to the side to face Japan at the Principality Stadium on Saturday and the 30-year-old British and Irish Lion said he struggled to get his head around such an uncharacteristic showing in Wales' first November international.
"I could think of a few four-letter expletives to describe how I played against Australia. The hardest thing was trying to find a reason why," he said.
"I'd been playing well and came into the camp with confidence but made mistakes I don't usually make.
"I did some soul-searching, had a few sleepless nights, and I certainly didn't deserve to play last weekend. It was an alien feeling, but one I learnt a hell of a lot from.
"It's given me a new perspective, a desire and hunger and a kick up the backside, which I hope, when I look back on this season, I realise I needed. That's the way I'm treating it. I don't know about redemption.
"I just want to prove to myself that it was an anomaly. I have to again stake my claim for the number 12 jersey and keep hold of it.
"I'm working on my weaknesses, but in moments like last week all of a sudden you have to think: 'What are my strengths that I can bring, and have traditionally brought, to this team?'
"People can write what they write but it hasn't served me too badly in my career."