Standard & Poor's 500 Index futures sank 0.6 per cent and the MSCI Asia Pacific Index (MXAP) lost 0.3 per cent.
Tsipras, 40, has pledged to win a writedown of Greek debt and abandon budget constraints imposed in return for aid, goals which Samaras said would risk Greece's exit from the euro bloc. Tsipras has said he'll keep the nation within the single currency area as he negotiates on the debt.
However, results suggest Syriza, which wants to renegotiate the terms of Greece's 240 billion ($361 billion) bailout deal with the EU and International Monetary Fund, had failed to win a majority.
Despite the tough rhetoric, Tsipras' party is likely to have to make concessions if it wants Greece to remain in the EU. While Greek debt, at 175 per cent of gross domestic product (GDP), remains at unsustainable levels, any debt relief will be met with fierce opposition from northern states, including Germany and Finland.
Greece has struggled under repeated rounds of austerity that have pushed unemployment up to 25 per cent compared with the eurozone average of 11.5 per cent.
However, other experts played down the likelihood of any large-scale fallout from Syriza taking power, arguing that the impact is likely to have been mitigated by the European Central Bank's 1.1 trillion bond-buying programme.
Number crunch
*Greek debt is 175% of gross domestic product.
*Austerity has pushed unemployment up to 25%.
*Syriza wants to renegotiate the $361 billion bailout.
- additional reporting Bloomberg