Ireland's most-capped prop failed to make the initial cut this time around but following Euan Murray's ankle injury, Hayes answered the Lions SOS call.
And the veteran front-rower could not hide his happiness at being handed another shot for the Lions in Cape Town.
Hayes, 35, said: "I'm delighted to get the late call-up and be here for two weeks and I can't wait - I'm just lucky enough that there was one midweek game left.
"It's hard to be hoping for a call because it means it is unfortunate for somebody else as every player has been called up because of an injury.
"It's the nature of a tour like this because there are a lot of games.
"I haven't played for a few weeks so I'm not looking further than the game on Tuesday. I'm just delighted to get the chance to play for the Lions again."
The Lions front-row and, in particular Phil Vickery, came under huge scrutiny after a tough examination from Springbok prop Tendai 'The Beast' Mtawarira. But Hayes reckons Ian McGeechan's men will bounce back in the second Test this Saturday in Pretoria.
"It was a huge start from the Springboks and they came out at a 100 miles per hour. They came quickly out of the blocks.
"But we are working on the scrum. It happened in the first half but things had sorted themselves out in the second. Hopefully we can get it right for Saturday."
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