Smith has compiled unbeaten innings of 89 in the Twenty20 match and 119 in South Africa's six wicket victory in Sunday's opening One-dayer in Centurion.
''He's obviously batted very well in the last two games and he's a key player for them,'' Buchanan told journalists today.
''He gives them good momentum at the top of the order and by the way he exudes himself on the field. So we've re-looked at our strategy - whether we can deliver is another matter.'' Buchanan was in buoyant mood after training today with the tourists needing to win Friday night's second One-day international to square the five match series.
''The last couple of days have been excellent and in terms of skills I'm very pleased with where we're at,'' he said.
''We have a couple of injuries we could do without but now it's just about the application of those skills on Friday night and on Sunday.'' Captain Ricky Ponting and all rounder Andrew Symonds both seem certain to miss Friday's match with muscle injuries.
However, the tourists were set to be boosted by the arrival of NSW batsman Phil Jaques tomorrow. ''When Phil arrives we will have 13 fit players and (selector) Andrew Hilditch arrives soon, too, so I guess they'll make a call on his selection soon,'' said Buchanan.
''He's been brought over to strengthen the top order, if selected, and he's enjoyed most of his success at the top of the order so I would think he's being seen as an opening batsman."