The Magners League duo are fighting it out for the full back berth in Ian McGeechan's team to face the world champion Springboks in Durban next week and the Irishman knows he has some ground to make up on his Welsh rival.
"I know that a solid game isn't going to be good enough to get me into the Test side so I'll be looking to show what I can do," said Kearney.
"There is a lot riding on this game and we all know there are Test places up for grabs.
This is only my second game on tour - I'd have liked to have had one or two more, so it is all or nothing now.
"It's all going to come down to Lee's performance on Wednesday against the Sharks and mine at Newlands. After that they'll weigh up the two options.
"All I want to do is go out and have a strong game to put myself in the strongest possible position. I just have to dig deep"
ends
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