Ayew is yet to score or provide an assist this season despite already playing seven matches in the Premier League.
The Ghanaian striker has now failed to register a goal in over 35 club games, a run that stretches to last season.
He has also failed to score for the Black Stars in almost a year, with his last goal – a penalty – coming against Sao Tome and Principe in November 2020.
“This problem [goal drought] is common among goal scorers,” Rajevac said when he addressed journalists on Friday.
“Sometimes, they have problems finding the back of the net and it is a difficult period for strikers in these times. However, we are here to support him, it is important for him to have our support.
“He knows this is a team game and it is important he contributes by scoring goals or providing assists but we hope his goal drought will end tomorrow.”
The Black Stars will play against Zimbabwe in Cape Coast on Saturday before travelling to Harare three days later for the return fixture.
Ghana currently sits in second place in Group G after two matches, having won against Ethiopia and lost to South Africa.