"It is a key for the All Blacks just to let things unfold around the fringes instead of jumping out of the line and when Genia does come forward, making sure you tackle him," said Gatland.
"You have got to keep him going laterally, that is the key to it. When he starts coming forward at you and someone comes out of the line, that's when he is dangerous."
Genia was a lethal rugby cocktail of speed, footwork, power and vision. When he offloaded he jumped back so he was difficult to take out of play.
Kurtley Beale was injured and not fit during the series and the Wallabies used Genia to cover the back part of the field with him.
Gatland said new wing Israel Folau was a great talent but still inexperienced in test rugby and he did not fall back in cover as much as others so there was space in behind him. He was a great addition to the ranks and midfield back Christian Leali'ifano was too, with the bonus of his goalkicking.
"The key to it though is trying to manipulate Genia so when he plays back, you crosskick or chip kick as options and when he is up you find space.
"That is the sort of approach the All Blacks have as well. You might play a few phases to get him up in the front line then work on the space he has left," said Gatland.
Deposed coach Robbie Deans stuck with James O'Connor at five-eighths for the Lions series but he was inexperienced in that role and did not get much space to flourish. His fantastic balance and skills were more effective in space wider out.
Captain James Horwill and new blindside Ben Mowen had been the Wallabies' most reliable forwards who had a strong workrate and defensive comprehension.
Several changes would come against the All Blacks so how did Gatland think that series would pan out?
"I think it will be a lot closer than people think. That Lions series was a lot tougher than people might have thought and the Wallabies should be reasonably battle-hardened from that.
"The Brumbies also showed in the Super 15 final that they are a difficult team to put away, they were very structured and that was effective and that should come through in the Wallabies," Gatland said.
"In fairness to the Chiefs they got it right in the end. We had the same issue when we played them. You have to go short, pick and go, get in behind them. If you are going to beat them it is going to be tough.
"They play territory, play off nine, play the short side, kick a lot, defend well and compete like hell at the breakdown. They work on getting space for the third man to put some heat on the ball at the breakdown."
Under McKenzie's stewardship, the Reds had been very smart about the subtleties in the game - areas on the edge of legality and they were also driven by the Genia-Quade Cooper axis.
That partnership was the likely starting Wallaby platform. Cooper had brought opportunities and mistakes as well when the Lions played the Reds.
In the tests, Gatland thought the Lions got into a little bit of trouble by playing too much rugby. That was fine as long as they were getting momentum rather than just shifting possession around.
"We became more direct particularly in the third test," he said.
Scrums were an area to attack the Wallabies and if referee Craig Joubert allowed that would be an intriguing part of next Saturday with the new scrum engagement laws.
"I'm not sure about the changes, said Gatland. "The issue with scrummaging isn't at any level apart from the very top. There are no issues elsewhere so it is only at the very elite."
Pre-binding should help the loosehead prop get a decent grip and that had been a big chunk of the problem for officials to understand what was happening at engagements.
Personal pride made up a large part of props' mentality, they would rather be penalised than shown up by some law they did not agree with.
The Lions thought they had a scrum advantage but had not been allowed to scrum the way they wanted in Brisbane and Melbourne. The Wallabies were smart at bringing the referee into play.
When Romaine Poite ordered scrums to be reset he was delivering a different message to the teams. That allowed the dominant Lions scrum to profit and use that platform to work from and create their momentum.
The Wallaby lineout was very competent, they claimed the bulk of their ball and disrupted the Lions when they tried to go off the middle or tail in the second test.
"They seem to be a team that feels if they stay in the game, the longer they go they will get a chance to win it," Gatland said.
