"With the tournament being expanded to six games each, there's even more chance than usual for us to see the Springboks play before they head over to Britain and Ireland in November," said McGeechan, who led the Lions to a series victory against the Springboks back in 1997.
"The Tri Nations is a very competitive tournament and it's one South Africa will want to do well in. They go into the competition as the best team in the world and I'm sure they'll want things to stay that way."
McGeechan, who recently embarked on a fact-finding mission in South Africa is currently getting ready for pre-season training with Guinness Premiership champions Wasps, but he insists the excitement of next year's Lions tour is already building.
"Gerald Davies and I learnt a great deal during our recent visit to South Africa and Saturday's game will probably tell us a little bit more about the challenge facing us this time next year.
"Everybody involved with the Lions is looking forward to next summer's tour and I think seeing South Africa in action over the next few weeks will only heighten that excitement."