Tonight's last provincial game on tour against the Emerging Springboks in Newlands in Cape Town is Williams's last chance to impress and he is determined to play his way into contention.
"I know that to have any chance of playing in the two remaining Tests I have to perform against the Emerging Springboks. That's why I come on these tours, to play in the Test matches. I want to play in them more than anything," he said.
Williams revealed Boks star man Bryan Habana spoke to him following the Lions' 26-21 opening Test defeat. "I spoke to Bryan and said how gutted I was at not playing in Durban. He replied: 'You never know, you might be playing next Saturday'.
Wiliams then added: "It's the last chance saloon. I realise how important this game is against a side I don't know much about. It's a match I want to get involved in as much as I can.
"I can assure you the effort will be there and I will be running my boots off. I will be letting myself down if I don't play well. If I do well, then who knows? Maybe I will have a chance of facing South Africa.
"There's nothing I want more than to be playing on Saturday and the following week. I know I have not played as well as I could have. But I have a lot more to give and need a big performance to be honest. I feel I have let nobody down but myself and I get angry thinking about it, so there's a lot - everything in fact - riding on this game."