Cameron van der Burgh (Getty)
Cape Town - Cameron van der Burgh and Jarred Crous have both failed to reach the semi-finals of the men's 200m breaststroke.
Van der Burgh finished seventh in his heat (2:12:67) while Crous was dead last in the following heat (2:12:64).
Crous' time was the 25th fastest, while Van der Burgh wound up one spot lower in 26th.
Only the top 16 progressed to the semi-finals.
Russia's Anton Chupkov was the fastest qualifier in 2:07:93.
The pair were the only two SA individual competitors in action in the pool on Day 4 in Rio.
In their heat for the men's 4x200m freestyle relay, the SA team of Myles Brown, Sebastien Rousseau, Calvin Justus and Dylan Bosch finished fifth in a time of 7:12:61, which was only good enough for 11th overall.
Great Britain were the fastest qualifiers in 7:06:31.
Team SA will be hoping Chad le Clos can lift his team-mates when he defends his title in the final of the 200m butterfly at 03:28 (SA time) on Wednesday.