South African captain Graeme Smith said he was surprised at the West Indies' approach on the first day of the fourth Test in St John's, Antigua on Friday.
Rain and bad light limited the day's play to just 48.5 overs but in that time South Africa, who won the toss and chose to bat, cruised to 214 without loss.
Smith was 106 not out with AB de Villiers on 103 as South Africa sought to claim a 3-0 win in the last match of the four-Test series.
"I didn't think twice about batting after I won the toss and I was surprised when I found out that the West Indies were going to bowl first if they had the choice," Smith told a news conference.
"It was also surprising that they took [fast bowler Tino] Best off after he started to reverse swing the ball and that they started with [medium pacer] Wavell Hinds after tea.
"We never allowed them to settle, but I think the West Indies gave up too early."
Smith said South Africa had taken the weather forecast into account.
"Our plan was to get a decent start, especially with the rain coming, and the rate we scored at helped to make up for the rain stoppages," he said.
Smith admitted that De Villiers played the more fluent innings.
"AB was superb, you can't get much better than 63 not out off 60 balls, which is what he had scored when we went off for rain the first time," Smith said.
The attacking De Villiers batted conservatively for his career best 178 in the third Test in Bridgetown, which South Africa won by an innings and 86 runs to clinch the series.
He was back to his aggressive best on Friday, driving, cutting and pulling with awesome power.
"I proved in Barbados that I can bat for a long time and my strokes will always be there," De Villiers said.
"They bowled a bit tighter at me when I reached the 80s but if the ball is there to be hit I will hit it."
Smith said his team did not lack motivation despite the series having been decided in Barbados.
"If we win here it's 100 Test victories for our country and three in a row on tour, which South Africa has never done before," Smith said.
Smith, De Villiers and the journalists they spoke to were accidentally locked into the room where the news conference took place.
The players and two of the reporters escaped by climbing over a slippery rail and onto a neighbouring stand and the door was eventually forced open by ground staff some 15 minutes after the news conference ended.