Stoke City midfielder Lawrence struck his first international goal in the 35th minute to complete a good week for Giovanni Trapattoni’s side following Saturday’s 2-1 win in Cyprus in a World Cup qualifier.
Kevin Doyle captained a side which featured only two players who started at the weekend as a number of fringe players were given the chance to impress in front of a poor crowd of just 11,300.
Kieron Westwood started in goal, with Eddie Nolan at left back and Caleb Folan partnering Doyle up front.
Ireland found themselves on the backfoot for a lot of the game as Everton’s Steven Pienaar pulled the strings for the visitors, though Westwood was never seriously troubled.
Coventry striker Leon Best impressed when introduced in the second half, and Trapattoni was overall pleased with the night’s work.
“I was asked what I wanted from this game and I said to play better than in Cyprus,” he told RTE.
“I looked for personality and it was a good performance.
“I am happy that the players have confirmed that this evening. It gives me hope to have a squad.”
Ireland - Westwood, Kelly, McShane, St Ledger, Nolan, Lawrence, Gibson, Andrews, Keogh, Folan, Doyle (capt).
Substitutes - Murphy, Duff, Miller, Best, McCarthy, Long, Whelan, O’Dea.
South Africa - Fernandez, Gaxa, Mokoena, Gould, Masilela, Van Heerden, Mhlongo, Dikgacoi, Pienaar, Mphela, Parker.
Substitutes - Baloyi, Ngobeni, Davids, Tshabalala, Mashego, Fransman, Thwala, Nkosi, Henyekane, Khumalo, Ngcongca, Khenyeza.