The Lions, in contrast, are fighting to stay alive following a 26-21 defeat in Durban last Saturday.
But forwards coach Gatland saw enough in the Lions' second-half performance - they fought back from 26-7 adrift - to confirm his belief the series is far from over.
And the Wales boss was not afraid to criticise South Africa's style of rugby as the Lions left their Cape Town base for a return to the Highveld.
"The South Africans have very much a bully mentality, to come in and try to dominate, pushing players off the ball," he said.
"You saw (Bryan) Habana getting into a player's face, and you saw (Bismarck) du Plessis.
"I would be very surprised if any of the Lions players take a backward step to any physical threat imposed by the South Africans.
"One of the things that surprised me about South Africa was how little rugby they played.
"They went to fourth phase once in the game, and I think the centres got one pass.
"There has always been a lot of criticism about northern hemisphere rugby, about us being quite boring and playing 10-man rugby.
"You wouldn't often give that criticism to teams like South Africa, but they didn't play any rugby at all."
If the Lions could deliver a series-levelling result, it would rank among the finest in their 118-year history.
But a Springboks team likely to be better than last week, plus a first game at altitude for the Lions in three weeks, means the odds are stacked against them.
Gatland insisted: "We think physically we are in great shape.
"We take a lot of heart out of the last 20 minutes (in Durban) when we had 80% of territory and possession and scored 14 points.
"We felt the South Africans were the team out on their feet, they were the guys with their hands on their knees and struggling with the game."