The former Wallabies scrum-half, who faced the Lions in 1989 and later led his country to the 1991 World Cup, reckons Genia and Mike Phillips are best nines in the game.
And he reckons the performances of Genia against Warren Gatland's men will be key to deciding the Test series.
"Genia I rate as the best, it's important that he be consistently good," said Farr-Jones.
"The good ball we get, Will's got to be able to use that well and his judgement's going to be really critical. He's playing with confidence, I think he'll want to dictate the series.
"I think Will will know, or at least be left in no doubt by (coach) Robbie Deans, that he need to have an outstanding series if we are to win. You need your best players playing at their best capacity.
"But he's up against a very physical, tough, big scrumhalf, who likes to niggle as well. It's going to be fascinating."
Genia has made no secret of the fact that he would prefer to play alongside Queensland Reds teammate Quade Cooper in the Gold and Green.
Cooper has been left out of the preliminary Wallabies squad but Farr-Jones reckons Robbie Deans should listen to his star scrum-half.
"I was lucky enough to play my first four tests with Mark Ella and the rest of my career with Michael Lynagh, it was critical to have someone you trusted, that you knew you had a great working relationship with," said Farr-Jones.
"It gives you confidence and particularly as a scrumhalf, one thing that you need is lateral vision and when you have confidence, you have lateral vision in spades.
"So knowing that the guy outside can do the job is critical. I have no doubt from a distance that Robbie Deans would listen to Will Genia (and) I'm sure Quade's still in the picture."
Back in 1989 Farr-Jones was part of a Wallabies side that lost a series to the Lions despite winning the first Test.
Farr-Jones is still haunted by the physical encounter now infamously known as the Battle of Ballymore and how the Wallabies let the series slip.
And he reckons Gatland's class of 2013 can inflict another telling blow on the Men from Down Under.
"Twenty-four years ago you get away with that more than you can now, you didn't have 14 cameras following the play, you didn't have touch judges with microphones and referees with ear pieces," added Farr-Jones.
"That hard, physical game, including rucking was more of an allowed thing in those days. I don't have a problem with the way they played, they played a very intelligent game. They looked at the first test, where we won by 18 points, and realised they had to change something.
"My only problem was that we didn't stand toe-to-toe. I have no doubt our guys will be well prepared mentally for the challenge. The boys are expecting it and there'll be some tough stuff.
"I think we've got a very good chance but if I was going to put my house on it three weeks out, I'd go with the British Lions because of the continuity they get in the lead-up."