The Welsh Grand Slam winner was not even in New Zealand a week ago, having been overlooked by Sir Clive Woodward for his original 45-man squad.
But a tour-ending injury to Scottish back-row star Simon Taylor opened the door for Jones, and he promptly barged it down by thrusting himself into Test squad contention.
The Neath-Swansea Ospreys forward scored a try and was hugely influential in all key areas as the Lions emerged unscathed from their trip to Otago's so-called 'House of Pain'.
Even head coach Woodward was almost lost for words when asked if he could explain how number eight Jones had not made the initial tour party, admitting: "No, I can't."
Jones, summoned from Wales' tour of North America last week, effortlessly transferred his blistering Six Nations form into the Lions arena - and the result was a spectacular arrival on rugby's world stage.
"The advice my father (Steve) gave me in the team hotel was to have 'no regrets', in what is a once-in-a-lifetime opportunity to be here," said Jones.
"I just wanted to give it 110%. Clive asked me to do a job, and I just went out there and played. A week ago, I wasn't here, so this is a dream come true.
"I only started my Test career last November, and having won a Grand Slam with Wales, it wouldn't have been a bad season had it just ended there! But this is incredible.
"I was in my hotel room in Toronto when the call came, and first of all, I thought it was one of the other boys taking the mickey.
"And then, coming here on the plane, I sat there thinking it was all quite daunting going out to be with so many seasoned international players, guys that I have always admired.
"But they've all been a massive help and they were great again, helping me through it."