"You have become the pride of our nation, we in turn request you to become victorious", Wickremesinghe told the players ahead of their knockout match in Sydney.
Third-placed Sri Lanka will not have it easy against second-placed South Africa, from pool B, at the SCG on Wednesday.
"You can do it, keep an eye on De Villiers".
President Maithripala Sirisena also wished the team and said in his message that he was extremely thankful to Kumar Sangakkara for his excellent feats that have helped push Sri Lanka to international heights.
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Both leaders wished Lanka the ability to return to the country victorious.
Sirisena's action stood in contrast with his predecessor.
Mahinda Rajapaksa travelled to watch games whenever a Sri Lankan team reaches finals including the last edition in 2011 in Mumbai.