Earls also picked up a shoulder injury during the game. The injury looked like it might threaten his participation in the rest of the tour, with tour doctor James Robson saying, 'in the past, Keith would almost certainly been out of the tour.'
The Munster sensation damaged his shoulder in two places and sustained deep bruising in the area and his chest, but he made a rapid recovery to score one of the tries of the tour just seven days later against the Cheetahs.
Earls has grown in stature since then, impressing in training and being handed more responsibility on the pitch with run-outs at both outside centre and full-back.
Looking more comfortable with each passing game, he donned the Lions number 15 jersey for the Emerging Springboks game and foiled the hosts' defence, stepping his way to a very well-taken first half try, his second of the tour.
Earls kicked well and was committed under every high ball, despite the wet and windy conditions.
Indeed, his performance was assured enough for some members of the media to wonder afterwards if he could come into the squad reckoning for the remaining Tests, particularly as he can cover full-back, centre and wing.
But wisely, the player himself is leaving the selection conundrums to Ian McGeechan and his management team.
"I'm not sure really. The two full-backs we have, Rob (Kearney) and Lee (Byrne), are great players and have a lot of experience," Earls said after his fifth game for the Lions.
"Hopefully I put my hand up tonight and gave the coaches something to think about.
"Obviously, I don't want to be known as a utility back. Hopefully 13 or 15 will be my position.
"I've enjoyed playing at 15 in the past two games and I played there at the start of the season with Munster, but due to an injury to Rua Tipoki I had to play at 13 and I enjoy both really."
Now the youngest member of the touring party, after Leigh Halfpenny's injury-enforced withdrawal, Earls had to dig deep both mentally and physically after coming under pressure in the first week of the tour.
Tuesday's display was further evidence that he has bounced back more determined than ever, lapping up each game as they come and oozing quality and class in attacking situations.
"Obviously it got off to a bad start in the first week, but I'm happy with the way it's gone since then," he said.
"I got two tries in a Lions jersey so I'm happy enough. It's my first season in senior rugby, I'm learning a lot and I still have a lot to learn.
"I was a bit bitter and a bit sad after my first game, but the lads I play with back home at Munster, Paulie (Paul O'Connell) and Rog (Ronan O'Gara), helped me get through it and I enjoyed the last couple of games.
"Playing for the Lions in a Test match is the highest achievement you can get and if it doesn't happen here, then the target will be to reach that goal in Australia in four years' time. It's something to aspire to."
The Limerick youngster, still only 21, must have groaned when he saw the heavy rain pelt down from over the Newlands stands, as a dry ball would have given a back-three containing Earls, Luke Fitzgerald and Shane Williams much more licence to thrill.
"This morning we saw the conditions and we thought, 'Jesus, how are we going to play fancy rugby in this?', but in fairness to the lads we got stuck in and did the best we could.
"Obviously we had to play the conditions, but apart from a few high balls in the swirling wind I'm happy enough with my performance."
This time last year, Earls was helping Ireland 'A' to victory in the Churchill Cup Plate final in Chicago. Now, just twelve months on, he is a fully-fledged Lion and his talent will hopefully shine for Munster, Ireland and the Lions for many years to come.
With Tuesday's game most probably his last appearance this season, he might finally get some time to reflect on how far he has come in such a short space of time.
"It's absolutely crazy. At the start of the season my goal was to get a few starts for Munster, but I started becoming a regular for Munster and I got a cap for Ireland and it was ridiculous, a dream come true really.
"And now to be on the Lions tour, it's just an unbelievable feeling."