Bafana suffered a 2-1 defeat to Cape Verde in Praia on Friday night. The result sees South Africa move down to second position.
“They will need to put up a better effort as a team collectively but they will need to improve their defence, as it let them down,” Vonk, who retired in 2011, told The Sowetan. “I think everyone involved will have to get their act together very quick.”
“The players, I think, are still getting used to the idea of having Stuart back as the coach after the departure of (Shakes) Mashaba.
“I have full trust in Baxter that he will get things right but as one can understand, results are immediately required from him as he took over in the middle of the qualifiers,” added Vonk.