Cape Town - Golden Lions coach Johan Ackermann has admitted to making a mistake when he substituted flyhalf Marnitz Boshoff in their 30-29 loss to the Cheetahs in Johannesburg on Saturday.Boshoff was replaced by Elton Jantjies in the second half and the latter missed a vital conversion late on which would have given the hosts victory.Boshoff's goal-kicking was impeccable all day and Ackermann said the initial plan was to shift Boshoff to fullback once Jantjies came on."I made the mistake to take the wrong man off the field," Ackermann told the Beeld website."We decided beforehand that should Elton come on, then we'll shift Marnitz to fullback and take Chrysander Botha off."With everything going on there was confusion and before I could realise what was going on, Marnitz was already off the field."It was important for us to have Marnitz's (kicking) boot on the field until the end."Ackermann said he wanted to get Jantjies on at flyhalf because Boshoff made a few errors on defence.The Lions' next game is against the Sharks in Durban on Friday (17:05 kick-off).