Yellow jersey holder Wiggins, seeking to become the first Briton to win the Tour, leads Evans by one minute 53 seconds midway through the three-week race, partly thanks to sports scientist Kerrison who had a swimming and rowing background.
When Wiggins was looking to bounce back from his 2010 Tour disappointment a year after finishing fourth overall, he turned to Australian Shane Sutton who brought in Kerrison, the man behind Australia's endurance swimming revolution who knew almost nothing about cycling.
"He made a massive difference," Wiggins, who leads Australian Evans after nine stages, told a news conference on Tuesday as the peloton enjoyed a rest day in the Beaujolais region.
"He changed my career. Since that 2010 disappointment, from that moment on we started working together with Shane.
"When I asked Shane to coach me, he was not comfortable he could do it all himself and he brought Tim in."
It was a bold move by Wiggins, who needed a bit of time to put his trust in a newcomer.
"It took a lot for me to trust him at the start because he had never worked in cycling, but he learned quickly," Wiggins said.
"He spent almost two years on the road in a camping car (following races)."
Kerrison made Wiggins race less but with the idea of winning every event he entered and his programme also includes training sessions at altitude in Tenerife, Spain, to help him cope with the Tour's toughest climbs.
The gamble has been paying off as Wiggins finished third overall in the Vuelta last year and won the Paris-Nice and Criterium du Dauphine stage races in the lead-up to this year's Tour.
"I would go as far as saying he revolutionised training in cycling within this team," said Wiggins, who sees Kerrison as the "brains" behind his improvement on the road.
There are, however, almost two weeks left on the Tour and Wiggins has too much "respect" for Evans to take anything for granted.
"We're expecting this to be a dogfight for the next two weeks, it's what cycling is about," Wiggins said.