Utility back Earls made his mark with the only Lions try in the 13-13 draw with the Emerging Springboks while prop Payne showed no signs of jetlag with an impressive display - just a day after arriving on tour.
And Gatland singled out the duo for praise just a few hours before the Lions management sit down to decide on who will be included in the 22 ahead of Saturday's make-or-break clash in Pretoria.
"It's a bit early to say after the game but I thought Tim Payne had a strong game after coming in for his first game. There were also some really nice touches from Keith, although there was probably one poor kick," said Gatland.
"I would need to have another look at the video but those two were probably the stand-outs. We've got difficult selections to make in terms of personnel and a couple of players put their hands up tonight.
"But we have to make sure we've not too reactive after the first Test because there were a heck of a lot of positives in terms of territory, possession and the fact we outscored South Africa by three tries to two."
The Lions led 10-3 at the interval against the young Springboks, who hit back in the last minute when Willem de Waal converted Danwel Demas' effort.
But Gatland defended the Lions players by insisting the changeable climate and the hosts' kicking strategy proved to be tough factors to cope with in a windswept abd rain lashed Cape Town.
"It was disappointing to concede the try at the end but the weather conditions weren't great and it became a kicking fest. But we didn't lose the game," said Gatland.
"Winning was important to us, and we wanted to do that, but it was difficult to play any positive rugby given the weather conditions. We came here to try and play some positive rugby but the weather didn't allow that.
"They kicked the leather off the ball but probably kicked better than we did at times."
Phil Vickery came off the bench in the second half, fresh from a tough match-up with Springbok prop Tendai 'The Beast' Mtawarira in the opening Test in Durban. And Gatland revealed he was delighted with the reaction of England's 'Raging Bull' at Newlands.
"It's great. It was difficult for him at the weekend and he's taken some criticism. But I was pleased with his run-out at the end and get back on the horse," said Gatland..
"There are eight guys responsible at scrum-time and the finger got pointed at one player, yet one player can't take full responsibility. We didn't scrummage well in the first half but we got that right in the second half last weekend."